Immunogenicity evaluation of prototype and variant inactivated SARS-CoV-2 vaccines in rats / 中国生物制品学杂志

@#Objective To evaluate the immunogenicity of prototype strain,Beta strain,Gamma strain and Delta strain of SARS-CoV-2 inactivated vaccines in rats.Methods Five female Wistar rats were immunized with SARS-CoV-2 inactivated vaccines of prototype,Beta,Gamma and Delta strains through thigh muscle twice at an interval of 14 d,with an immunization dose of 3 μg virus protein/(0.5 mL per rat).Serum samples were collected and isolated by vein 14,28 and 42 d after the first immunization.The serum IgG antibody levels were detected by indirect ELISA,the titers of serum neutralizing antibody were measured by microneutralization,and the antigenic ratios of the serum neutralizing antibody titers were calculated to evaluate the antigenicity difference between different strains.Results at 14 d after the first immunization,IgG antibodies against four strains of virus were detected in all immunized serum samples.The levels of IgG antibodies increased by more than 10 times at 28 d compared with those at 14 d,and decreased slightly at 42 d.At 14 d after the first immunization,all the neutralizing antibodies against the four strains were positive in the serum of rats immunized with prototype strain or Delta strain vaccine;In the serum samples of rats immunized with Beta and Gamma strains,all the neutralizing antibodies against Beta and Gamma strains were positive,while some neutralizing antibodies against prototype or Delta strains were positive.At 28 d after the first immunization,the neutralizing antibodies in the immune serum of the four strains were positive,and the titers of neutralizing antibodies were significantly higher than those at 14 d;The neutralizing antibody titers were slightly lower at 42 d after the first immunization than 28 d.There was small difference in the antigenicity between Beta and Gamma,prototype and Gamma,but significant difference in the antigenicity between prototype and Beta strains.Conclusion The prototype strain,Beta strain,Gamma strain and Delta strain of SARS-CoV-2 inactivated vaccines can stimulate rats to produce neutralizing antibodies with high titer,while the immunogenicity has difference.

Immunogenicity of COVID-19 adsorbed inactivated vaccine (CoronaVac) and additional doses of mRNA BNT162b2 vaccine in immunocompromised adults compared with immunocompetent persons

ABSTRACT Inactivated COVID-19 vaccines data in immunocompromised individuals are scarce. This trial assessed the immunogenicity of two CoronaVac doses and additional BNT162b2 mRNA vaccine doses in immunocompromised (IC) and immunocompetent (H) individuals. Adults with solid organ transplant (SOT), hematopoietic stem cell transplant, cancer, inborn immunity errors or rheumatic diseases were included in the IC group. Immunocompetent adults were used as control group for comparison. Participants received two CoronaVac doses within a 28-day interval. IC received two additional BNT162b2 doses and H received a third BNT162b2 dose (booster). Blood samples were collected at baseline, 28 days after each dose, pre-booster and at the trial end. We used three serological tests to detect antibodies to SARS-CoV-2 nucleocapsid (N), trimeric spike (S), and receptor binding domain (RBD). Outcomes included seroconversion rates (SCR), geometric mean titers (GMT) and GMT ratio (GMTR). A total of 241 IC and 100 H adults participated in the study. After two CoronaVac doses, IC had lower SCR than H: anti-N, 33.3% vs 79%; anti-S, 33.8% vs 86%, and anti-RBD, 48.5% vs 85%, respectively. IC also showed lower GMT than H: anti-N, 2.3 vs 15.1; anti-S, 58.8 vs 213.2 BAU/mL; and anti-RBD, 22.4 vs 168.0 U/mL, respectively. After the 3rd and 4th BNT162b2 doses, IC had significant anti-S and anti-RBD seroconversion, but still lower than H after the 3rd dose. After boosting, GMT increased in IC, but remained lower than in the H group. CoronaVac two-dose schedule immunogenicity was lower in IC than in H. BNT162b2 heterologous booster enhanced immune response in both groups.

Evaluation of three alum-precipitated Aeromonas hydrophila vaccines administered to Labeo rohita, Cirrhinus mrigala and Ctenopharyngodon idella: immunokinetics, immersion challenge and histopathology / Avaliação de três vacinas de Aeromonas hydrophila precipitadas com alúmen administradas a Labeo rohita, Cirrhinus mrigala e Ctenopharyngodon idella: imunocinética, desafio de imersão e histopatologia

Aeromonas hydrophila is a cause of infectious disease outbreaks in carp species cultured in South Asian countries including Pakistan. This bacterium has gained resistance to a wide range of antibiotics and robust preventive measures are necessary to control its spread. No prior use of fish vaccines has been reported in Pakistan. The present study aims to develop and evaluate inactivated vaccines against local strain of A. hydrophila in Pakistan with alum-precipitate as adjuvant. The immunogenic potential of vaccine was evaluated in two Indian major carps (Rohu: Labeo rohita, Mori: Cirrhinus mrigala) and a Chinese carp (Grass carp: Ctenopharyngodon idella). Fish were vaccinated intraperitoneally followed by a challenge through immersion. Fish with an average age of 4-5 months were randomly distributed in three vaccinated groups with three vaccine concentrations of 108, 109 and 1010 colony forming unit (CFU)/ml and a control group. Fixed dose of 0.1ml was applied to each fish on 1st day and a booster dose at 15 days post-vaccination (DPV). Blood samples were collected on 14, 28, 35, 48 and 60 DPV to determine antibody titers in blood serum using compliment fixation test (CFT). Fish were challenged at 60 DPV with infectious A. hydrophila with 108 CFU/ml through immersion. Significantly higher levels of antibody titers were observed from 28 DPV in all vaccinated groups as compared to those in the control group. In challenge experiment the average RPS (relative percent survivability) was 71% for groups vaccinated with 109 and 1010 CFU/ml and 86% for 108 CFU/ml. Vaccine with 108 CFU/ml induced highest immune response followed by 109 and 1010 CFU/ml. The immune response of L. rohita and C. idella was better than that of C. mrigala. In general, normal histopathology was [...].

Aeromonas hydrophila é uma causa de surtos de doenças infecciosas em espécies de carpas cultivadas em países do sul da Ásia, incluindo o Paquistão. Essa bactéria ganhou resistência a uma ampla gama de antibióticos, e medidas preventivas robustas são necessárias para controlar sua disseminação. Nenhum uso anterior de vacinas para peixes foi relatado no Paquistão. O presente estudo tem como objetivo desenvolver e avaliar vacinas inativadas contra cepa local de A. hydrophila no Paquistão com precipitado de alúmen como adjuvante. O potencial imunogênico da vacina foi avaliado em duas carpas principais indianas (Rohu: Labeo rohita, Mori: Cirrhinus mrigala) e uma carpa chinesa (Grass Carp: Ctenopharyngodon idella). Os peixes foram vacinados por via intraperitoneal, seguido de um desafio por imersão. Peixes com idade média de 4-5 meses foram distribuídos aleatoriamente em três grupos vacinados com três concentrações de vacina de 108, 109 e 1010 unidades formadoras de colônias (UFC) / ml e um grupo de controle. Foi aplicada dose fixa de 0,1ml em cada peixe no 1º dia e dose de reforço 15 dias pós-vacinação (DPV). Amostras de sangue foram coletadas em 14, 28, 35, 48 e 60 DPV para determinar os títulos de anticorpos no soro sanguíneo usando o teste de fixação de elogio (CFT). Os peixes foram desafiados a 60 DPV com infecciosa A. hydrophila com 108 CFU / ml por imersão. Níveis significativamente mais elevados de títulos de anticorpos foram observados em 28 DPV em todos os grupos vacinados, em comparação com aqueles no grupo de controle. Na experiência de desafio, o RPS médio (sobrevivência percentual relativa) foi de 71% para os grupos vacinados com 109 e 1010 CFU / ml e 86% para 108 CFU / ml. A vacina com 108 UFC / ml induziu a maior resposta imune seguida por 109 e 1010 UFC / ml. A resposta imune de L. rohita e C. idella foi melhor do que a de C. mrigala. Em geral, histopatologia normal foi observada em diferentes [...].

Evaluation of three alum-precipitated Aeromonas hydrophila vaccines administered to Labeo rohita, Cirrhinus mrigala and Ctenopharyngodon idella: immunokinetics, immersion challenge and histopathology

Abstract Aeromonas hydrophila is a cause of infectious disease outbreaks in carp species cultured in South Asian countries including Pakistan. This bacterium has gained resistance to a wide range of antibiotics and robust preventive measures are necessary to control its spread. No prior use of fish vaccines has been reported in Pakistan. The present study aims to develop and evaluate inactivated vaccines against local strain of A. hydrophila in Pakistan with alum-precipitate as adjuvant. The immunogenic potential of vaccine was evaluated in two Indian major carps (Rohu: Labeo rohita, Mori: Cirrhinus mrigala) and a Chinese carp (Grass carp: Ctenopharyngodon idella). Fish were vaccinated intraperitoneally followed by a challenge through immersion. Fish with an average age of 4-5 months were randomly distributed in three vaccinated groups with three vaccine concentrations of 108, 109 and 1010 colony forming unit (CFU)/ml and a control group. Fixed dose of 0.1ml was applied to each fish on 1st day and a booster dose at 15 days post-vaccination (DPV). Blood samples were collected on 14, 28, 35, 48 and 60 DPV to determine antibody titers in blood serum using compliment fixation test (CFT). Fish were challenged at 60 DPV with infectious A. hydrophila with 108 CFU/ml through immersion. Significantly higher levels of antibody titers were observed from 28 DPV in all vaccinated groups as compared to those in the control group. In challenge experiment the average RPS (relative percent survivability) was 71% for groups vaccinated with 109 and 1010 CFU/ml and 86% for 108 CFU/ml. Vaccine with 108 CFU/ml induced highest immune response followed by 109 and 1010 CFU/ml. The immune response of L. rohita and C. idella was better than that of C. mrigala. In general, normal histopathology was observed in different organs of vaccinated fish whereas minor deteriorative changes were found in fish vaccinated with higher concentrations of the vaccine.

Resumo Aeromonas hydrophila é uma causa de surtos de doenças infecciosas em espécies de carpas cultivadas em países do sul da Ásia, incluindo o Paquistão. Essa bactéria ganhou resistência a uma ampla gama de antibióticos, e medidas preventivas robustas são necessárias para controlar sua disseminação. Nenhum uso anterior de vacinas para peixes foi relatado no Paquistão. O presente estudo tem como objetivo desenvolver e avaliar vacinas inativadas contra cepa local de A. hydrophila no Paquistão com precipitado de alúmen como adjuvante. O potencial imunogênico da vacina foi avaliado em duas carpas principais indianas (Rohu: Labeo rohita, Mori: Cirrhinus mrigala) e uma carpa chinesa (Grass Carp: Ctenopharyngodon idella). Os peixes foram vacinados por via intraperitoneal, seguido de um desafio por imersão. Peixes com idade média de 4-5 meses foram distribuídos aleatoriamente em três grupos vacinados com três concentrações de vacina de 108, 109 e 1010 unidades formadoras de colônias (UFC) / ml e um grupo de controle. Foi aplicada dose fixa de 0,1ml em cada peixe no 1º dia e dose de reforço 15 dias pós-vacinação (DPV). Amostras de sangue foram coletadas em 14, 28, 35, 48 e 60 DPV para determinar os títulos de anticorpos no soro sanguíneo usando o teste de fixação de elogio (CFT). Os peixes foram desafiados a 60 DPV com infecciosa A. hydrophila com 108 CFU / ml por imersão. Níveis significativamente mais elevados de títulos de anticorpos foram observados em 28 DPV em todos os grupos vacinados, em comparação com aqueles no grupo de controle. Na experiência de desafio, o RPS médio (sobrevivência percentual relativa) foi de 71% para os grupos vacinados com 109 e 1010 CFU / ml e 86% para 108 CFU / ml. A vacina com 108 UFC / ml induziu a maior resposta imune seguida por 109 e 1010 UFC / ml. A resposta imune de L. rohita e C. idella foi melhor do que a de C. mrigala. Em geral, histopatologia normal foi observada em diferentes órgãos de peixes vacinados, enquanto pequenas alterações deteriorantes foram encontradas no grupo de controle e nos peixes vacinados com concentrações mais altas da vacina.

Study on the change of neutralizing antibody level in plasma donors after a third shot of inactivated novel coronavirus vaccine / 中国输血杂志

【Objective】 To investigate the trend of neutralizing antibody level in plasma donors who received the 3rd shot of inactivated novel coronavirus vaccine. 【Methods】 Three commercial ELISA kits for novel coronavirus neutralization antibody detection, manufactured by Company A, B and C, were chosen and screened by Pseudotype Neutralization Test from December 2021 to June 2022. A total of 410 plasma samples from 64 plasma donors who received the 3rd shot of inactivated novel coronavirus vaccine and there after donated plasma within six months were detected by the selected ELISA kit from July to October, 2022. The data were analyzed by Excel 2013 and SPSS 26 software. 【Results】 The high-throughput ELISA kit for SARS-CoV-2 neutralizing antibody detection, manufactured by Company A, was selected for further antibody titer detection. The mixed plasma titers were 1 337.34, 1 148.89, 852.19, 681.38, 556.44 and 457.19 U/mL from 1 to 6 months, respectively, after the 3rd shot of vaccine. The neutralizing antibody titer level began to increase around 7 days after the 3rd shot of vaccine injection and peaked (peak range: 264.07-2 208.39 U/mL, median: 569.34 U/mL) at 1 month (range: 9-43 days, median: 22 days), and then gradually decreased (P<0.05). 【Conclusion】 The neutralizing antibody titer of plasma donors who received the 3rd shot of inactivated novel coronavirus vaccine began to rise around 7 days after vaccination, which reached the peak value at around 1 month and then gradually decreased.

Quality evaluation of inactivated poliomyelitis vaccine made from Sabin strains after optimization / 中国生物制品学杂志

@#Objective To evaluate the product quality of inactivated poliomyelitis vaccine made from Sabin strains(sIPV)after optimization of preparation formula.Methods The quality attributes of sIPV products after preparation optimization(no phenol red and no bacteriostatic agent)were evaluated,and the quality comparability with the listed sIPV products was analyzed;270 Wister rats of half male and half female were immunized with the finished products before and after preparation optimization simultaneously by intramuscular injection,measured for the level of neutralizing antibody in serum,evaluated for the immunogenicity,and analyzed for the compa-rability;The finished products with optimized preparation were placed at 37 ℃,room temperature(20～25 ℃)and 2～8 ℃ for accelerated and long-term stability tests separately,detected for the content of key indicator D antigen to evaluate the stability,and analyzed for the comparability with historical data of the listed products.Results After preparation formula optimization,the detection results of the sIPV vaccine for typeⅠ,Ⅱ,and Ⅲ D antigen content,protein content,pH value,Vero cell protein residue,bovine serum albumin residue,Vero cell DNA residue,and free formaldehyde content all conformed to the requirements of Chinese Pharmacopoeia Ⅲ (2020 edition)and the enterprise standard. Before and after the process optimization,the quality attributes,immunogenicity and accelerated and long-term stability trends were consi-stent.Conclusion The formulation of the optimized sIPV vaccine no longer contains phenol red and bacteriostatic agent ingredients,of which the safety has been improved;The quality attributes,immunogenicity,and stability of the product are highly similar to those before optimization;All indicators met the requirements during the validity period and the product has good stability.

Serum neutralizing antibody following the vaccination of inactivated SARS-CoV-2 vaccines / 上海预防医学

ObjectiveTo determine the difference of serum neutralizing antibody levels in healthy persons following the vaccination of inactivated SARS-CoV-2 vaccines. MethodsHealth care workers that received inactivated SARS-CoV-2 vaccines were enrolled in Sichuan provincial people's hospital from January to December 2021. All participants were classified into four groups according to the number and time of vaccination， which were groups of 28 days after the second dose， 180 days after the second dose， 28 days after the third dose and 150 days after the third dose. Serum neutralizing antibody was quantitatively detected by chemiluminescence method. Furthermore， the serum neutralizing antibody levels were compared within and between groups by gender， age and body mass index（BMI）. ResultsA total of 349 participants were enrolled in this study， including 113 males and 236 females. The positive rates of neutralizing antibody in the groups of 28 days after the second dose， 180 days after the second dose， 28 days after the third dose and 150 days after the third dose were 74.0%， 25.7%， 100.0% and 100.0%， respectively. In the four groups， neutralizing antibody levels were 10.38 （5.76， 24.00） AU·mL-1， 4.18 （3.00， 6.18） AU·mL-1， 41.18 （25.80， 116.21） AU·mL-1 and 33.33 （18.09， 69.12） AU·mL-1， respectively. The positive rate of neutralizing antibody significantly differed across the groups （P<0.001）. Furthermore， neutralizing antibody level in the third dose groups were significantly higher than that in the second dose groups （P<0.001）. Neutralization antibody level in young people （<45 years old） was significantly higher than that in middle-aged and elderly people （≥45 years old） in the groups of 180 days after the second dose and 28 days after the third dose （P<0.05）. Additionally， neutralization antibody level in normal weight participants was significantly higher than that in overweight and obese participants in the group of 28 days after the second dose （P<0.05）. However， no significant difference was found in all groups by gender （P>0.05）. ConclusionCompared with two doses of inactivated SARS-CoV-2 vaccine， three doses can significantly induce higher neutralizing antibody and stronger immune protection. Age and BMI have certain effect on the neutralizing antibody.

Development and verification of double antibody sandwich ELISA method for determination of D antigen content in s IPV vaccine / 中国生物制品学杂志

@#Objective To develop and verify a sandwich ELISA method with bovine polyclonal antibody against rabbit polyclonal antibody for the determination of D antigen content of Sabin strain inactivated poliovirus vaccine(sIPV).Methods The rabbit polyclonal antibodies were prepared with sIPV vaccine bulks of type Ⅰ,Ⅱ and Ⅲ as antigens and detected for the titer and specificity by indirect ELISA.A double antibody sandwich ELISA with bovine polyclonal antibody as coating antibody and rabbit polyclonal antibody as detection antibody was developed to determine D antigen content,and the accuracy,precision and specificity to D antigen of the method were verified.sIPV vaccine samples from five domestic enterprises were detected by the developed method.Results The rabbit polyclonal antibodies for type Ⅰ,Ⅱ and Ⅲ sIPV with good specificity and high titer were prepared,and the double antibody sandwich ELISA method was successfully developed.Using four-parameter fitting,all three standard curves showed good linear relationship,and R~2 values were more than 0.99.The spike recoveries of type Ⅰ,Ⅱ and Ⅲ D antigens were all within 80%～120%,with average values of98.11%,97.41% and 98.66%,respectively.The CVs of repeatability and intermediate precision were all below 10%.The method also distinguished D antigens from C antigens.The developed method determined the D antigen contents of sIPV vaccines from five enterprises.Conclusion A sandwich ELISA method for determination of D antigen content in sIPV vaccine was successfully developed with satisfying accuracy,precision and certain D antigen specificity,which can be used to detect vaccines produced by different manufacturers.

Preparation of the second generation internal control reference for anti-SARS-CoV-2 IgG antibody and evaluation of its applicability in ELISA detection method / 中国生物制品学杂志

@#Objective To prepare the second generation internal control reference(B2)for Ig G antibody against severe acute respiratory symptom coronavirus 2(SARS-CoV-2)and evaluate its applicability in ELISA detection method. Methods Among the volunteers vaccinated with SARS-CoV-2 inactivated vaccine(BBIBP-Cor V)produced by Beijing Institute of Biological Products Co.,Ltd.,19 Ig G antibody positive plasma samples with ELISA-Ig G dilution ratio of 20 ～ 60 were screened,and the Ig G antibody,IgM antibody and neutralizing antibody were detected by ELISA,B2 was prepared from nonlipid plasma with ELISA-Ig G dilution ratio of 32 ～ 45,IgM negative and similar neutralizing antibody inhibition rate. The neutralizing antibody potency of the first generation internal control reference(B1)and B2 detected by ELISA was calibrated with the first generation WHO international standard of anti-SARS-CoV-2 immunoglobulin(NIBSC 20/136),and the accelerated stability(storage at 2 ～ 8 ℃ for 5,8,14,20,and 30 d respectively),the service stability(storage at 18 ～25 ℃ for 1,2,and 3 h respectively),the freeze-thaw stability(1,2 and 3 times)and the long-term stability(storage at-25 ℃ for10 months)of B2 were tested. B2 was used as standard to detect plasma after single vaccine immunization and mixed plasma was prepared according to different ELISA-Ig G dilution ratio. The correlation and linear regression analysis between ELISA-Ig G dilution ratio and neutralizing antibody potency of pseudovirus in mixed plasma were carried out. Results Among 19 plasma samples,5 samples were non-lipid plasma with ELISA-Ig G dilution ratio of 32 ～ 45,IgM negative and similar neutralizing antibody inhibition rate. B2 was prepared by mixing every plasma in equal volume fraction,and the dilution ratio of ELISA-Ig G was assigned to 32. The neutralizing antibody potency of B1 calibrated with NIBSC 20/136 was 133. 38 EIU/m L and that of B2 was 122. 14 EIU/m L. The recovery rates of accelerated stability,service stability,freeze-thaw stability and long-term stability of B2 were all in the range of(100 ± 15)%. The ELISA-Ig G dilution ratio of the mixed plasma from the same source was significantly correlated with the neutralizing antibody potency of pseudovirus.(each R~2> 0. 99,each P < 0. 000 1).Conclusion B2 prepared from plasma immunized with SARS-CoV-2 inactivated vaccine can replace B1 prepared from plasma of COVID-19 convalescent patients.

Development and verification of a quantitative real-time PCR method for determination of host cell DNA residues in inactivated SARS-CoV-2 vaccine(Vero cells) / 中国生物制品学杂志

@#Objective To develop and verify a quantitative real-time PCR method for determination of the content of host cell DNA residues in severe acute respiratory symptom coronavirus 2(SARS-CoV-2) inactivated vaccine(Vero cells),in order to better control the safety of products.Methods DNA was extracted from inactivated SARS-CoV-2 vaccine(Vero cells) bulk by magnetic bead separation method,and the DNA residues of host cells were quantitatively analyzed by probetype PCR.The linear range,repeatability,intermediate precision,quantitative limit,specificity,durability and accuracy of the developed method were verified,and the host cell DNA re sidues of 5 batches of inactivated SARS-CoV-2 vaccine(Vero cells)were determined by this method.Results DNA standard curve showed good linearity in the range of 300～0.003 pg/μL(each R~2> 0.99);Relative standard deviations(RSD) of repeatability and intermediate precision verification were less than 20%;The quantitative limit was 0.001 pg/μL;Sample dilution and purified liquid dilution had no interference to detection;The results of 60 min incubation at 53,55,57 ℃ and 56,60,64 min incubation at 55 ℃ showed no significant difference;The recoveries of accuracy verification were 79%～83%,RSD <5%.This method had good adaptability in detecting DNA residues in the bulk of inactivated SARS-CoV-2 vaccine(Vero cells).Conclusion The quantitative realtime PCR method for determination of host cell DNA residues in inactivated SARS-CoV-2 vaccine(Vero cells) has been successfully developed,of which the linearity and range,repeatability,intermediate precision,quantitative limit,specificity,durability and accuracy meet the acceptable standards,and are suitable for the detection and quality control of host cell DNA residues in inactivated SARS-CoV-2 vaccine(Vero cells).

Absorption characteristics of aluminum hydroxide adjuvant with inactivated enterovirus 71 / 中国生物制品学杂志

@#Objective To explore the absorption characteristics of aluminum hydroxide adjuvant with inactivated enterovirus 71(EV71).Methods The morphology,purity and particle size distribution of inactivated EV71 particles were analyzed by transmission electron microscope,size exclusion chromatography HPLC(SEC-HPLC) and dynamic light scatter(DLS),and the morphology of aluminum hydroxide adjuvant nanoparticles was observed by transmission electron microscope.Using inactivated EV71 antigen content(4 000,6 000,8 000,10 000,11 000,12 000,13 000,14 000,20 000,30 000 U/mL),aluminum hydroxide adjuvant concentration [0.35,0.25,0.17,0.085 mg/mL(aluminum content)],adsorption time(0.30 and 120 min),ionic strength(sodium chloride concentration of 0.15,0.75 and 1.25 mol/L)and phosphorus-aluminum molar ratio(P/Al,0.15,0.64,2.08 and 7.87) as variables,the adsorption characteristics of aluminum hydroxide adjuvant with inactivated EV71 antigen were investigated.Results Inactivated EV71 particles mainly existed in the form of intact virus particles with a diameter of about 30 nm;Aluminum hydroxide adjuvant showed the characteristics of nanocrystallization,and the particle size was distributed within 200～700 nm.The inactivated EV71 antigen at the concentration of no more than 11 000 U/mL was completely absorbed by aluminum hydroxide adjuvant of 0.35 mg/mL(aluminum content),and no free antigen was detected in the supernatant;while from 12 000 U/mL,the content of free antigen in the supernatant increased with the increase of antigen content;the inactivated EV71 antigen of 250 U/mL was completely absorbed by various concentrations of aluminum hydroxide adjuvant,and no free antigen was detected in the supernatant;the adsorption effect of aluminum hydroxide adjuvant consistent after incubation for different time,and no free antigen was detected in the supernatant.Under the conditions of single dose of vaccine with aluminum hydroxide content(0.35 mg/mL) and inactivated EV71 antigen content(250 U/mL),sodium chloride ion strength had no effect on the adsorption of inactivated EV71 virus,while phosphate ion concentration significantly effected the adsorption.Conclusion Aluminum hydroxide adjuvant in a single dose of vaccine completely absorbed inactivated EV71 antigen,and group replacement played an important role.

Immune persistence following intradermal vaccination with fractional dose of diphtheria-tetanus-acellular component pertussis and Sabin-derived inactivated poliovirus vaccine / 中国生物制品学杂志

Objective@#To evaluate the immune persistence following intradermal(ID) vaccination with diphtheria-tetanusacellular component pertussis and Sabin-derived inactivated poliovirus vaccine(DTacP-sIPV).@*Methods@#40 wistar rats were randomly assigned into four groups.Two test groups were injected intradermally with fractional-doses(1/5 and 1/10dose) of DTacP-sIPV(1/5D ID and 1/10D ID group);The positive control group was intramuscularly injected with full dose of DTacP-sIPV(full-dose IM group);The negative control group was injected with PBS intradermally.Wistar rats were immunized 3 times at 0,1 and 2 months and the blood samples were collected via tail vein 12 months after the last immunization and the serum samples were isolated.The titer of neutralizing antibody against poliovirus was detected by micro-neutralization test,and the titers of IgG antibodies against diphtheria toxin(DT),tetanus toxin(TT),pertussis toxin(PT),filamentous hemagglutinin(FHA) and pertactin(PRN) in rat serum were detected by indirect ELISA.The geometric mean titer(GMT)and positive rate of antibody were calculated.The rats were challenged with aerosolized B.pertussis for 30 min 12 months after the last immunization and determined for the white blood cell(WBC) count and colony-forming unit(CFU) in lung,trachea and nose at day 2,5 and 14 after challenge.@*Results@#Compared with the full-dose IM group,there was no significant difference in the positive rates of poliovirus type Ⅰ,Ⅱ and Ⅲ neutralizing antibodies between 1/5D ID and 1/10D ID groups(each P> 0.05) and the positive rates of all types of antibodies in the control group were 0.The positive rates of IgG antibodies against DT,TT,PT,FHA and PRN in 1/5D ID,1/10D ID and full-dose IM groups were all 100%,and those in control group were all 0.Compared with 2 d after challenge,the WBC counts of rats in control group increased significantly 5 d after aerosol challenge with B.pertussis(F=3.48,P <0.05),and then began to decrease,while those in other groups remained stable with time(F=0.14～1.30,P> 0.05).After aerosol challenge,the CFU in lungs of rats in control group was significantly higher than that in the other three groups(F=19.00～206.00,P<0.05),and B.pertussis was still detected 14 d after challenge;Except for the control group,the bacterial load in lungs of rats in the other three groups reached the peak 5d after challenge,the B.pertussis was basically cleared on the 14d,and there was no significant difference among the groups at each time point(F=1.14～1.25,P> 0.05).The bacterial load of trachea and nose in the control group was slightly higher than that in other groups at each time point,but the difference was not significant(F=0.71～3.54,P> 0.05).Except for the control group,the bacterial load in the trachea and nose of the other three groups were similar,and no significant difference was observed(F=0.75～3.41,P>0.05).@*Conclusion@#ID immunization with1/5 dose of DTacP-sIPV induced persistent protective antibodies against various components of the vaccine in rats.This study provided an experimental basis for the formulation of immunization strategy of ID immunization with fractional dose of DTacP-sIPV.

Acute adverse events and pregnancy outcome after inactivated COVID-19 vaccination in first trimester / 中华围产医学杂志

Objective:To investigate acute adverse events and pregnancy outcome after vaccination of inactivated COVID-19 vaccine in the first trimester of pregnancy.Methods:The retrospective-prospective cohort study was conducted among pregnant women of 11-13 +6 weeks of gestation who visited the obstetric clinics for prenatal check in Lianyungang Maternal and Child Health Hospital from May to November in 2021, after registration for perinatal health cards in the community. Those who met the inclusion criteria were recruited and were divided into vaccination group and non-vaccination group according to whether they received inactivated COVID-19 vaccine in the first trimester. Women in the vaccination group were further divided into 1-dose group and 2-dose group. Information, including pregnancy-related screening, pregnancy complications, pregnancy outcome and acute adverse events, were collected and compared with independent samples t-test or ANOVA, Kruskal- Wallis H test or Mann-Whitney U test, χ2 test or Fisher's exact probability method. Results:Totally, 105 pregnant women were analyzed in 1-dose group, 90 in 2-dose group, and 194 in non-vaccination group. (1) There were no statistically significant differences in the occurrence of acute adverse events [1-dose group: 2.86% (3/105); 2-dose group: 6.67% (6/90); non-vaccination group: 4.63% (9/194); χ2=1.59; vaccination group was 4.61% (9/195), when compared with non-vaccination group, χ2=0.00], abnormal pregnancy-related screening indicators and abnormal pregnancy outcome among the three groups (all P>0.05), neither between the vaccination and non-vaccination group (all P>0.05). The acute adverse events in these women included fever, pain at the inoculation site, fatigue, local induration and rash.(2) The differences in hypertensive disorders in pregnancy among the three groups were statistically significant [1-dose group: 10.5%(11/105); 2-dose group: 17.8%(16/90); non-vaccination group: 7.7%(15/194); χ2=6.46, P=0.040], and the incidence was higher in the 2-dose group than that in the non-vaccination group (adjusted by Bonferroni, P<0.017). (3) Regarding other pregnancy complications, no difference was found among the three groups (all P>0.05), neither between the vaccination and non-vaccination group (all P>0.05). Conclusion:The risk of acute adverse events and adverse pregnancy outcome is similar in pregnant women who received inactivated COVID-19 vaccine versus those who did not in the first trimester, and regular blood pressure monitoring is recommended for those who received two doses of inactivated COVID-19 vaccine.

Correlation of serum antibody titers with clinical features and prognosis of anti leucine-rich glioma inactivated 1 antibody encephalitis / 中华神经科杂志

Objective:To analyze the relationship between serum antibody titers, clinical characteristics, and prognosis in patients with encephalitis induced by anti leucine-rich glioma inactivated 1 (LGI1) antibody.Methods:Clinical data of 20 patients diagnosed with encephalitis in the Department of Neurology, First Hospital of Shanxi Medical University from February 2015 to February 2021 were collected and retrospectively analyzed. Patients were divided into 2 groups based on their serum anti LGI1 antibody titers, namely the high titer group (1∶100, 1∶320) and the low titer group (1∶10, 1∶32). The clinical characteristics, laboratory test results, and prognosis of the 2 groups of patients were compared. Relusts The age of the 20 patients with anti LGI1 antibody encephalitis ranged from 27 to 69 (53.5±11.2) years, with a male to female ratio of 1∶1. There were 9 patients in the low titer group and 11 patients in the high titer group. There was no statistically significant difference in the types and quantities of clinical symptoms between the 2 groups. Patients in the high titer group were more prone to abnormal lesions on cranial magnetic resonance imaging (10/11 vs 3/9, P=0.014). There was no statistically significant difference between the 2 groups in the presence or absence of cerebrospinal fluid anti LGI1 antibodies (9/11 vs 4/9, P=0.160). During the follow-up, it was found that 1/20 patient died of pulmonary embolism, 7/20 of patients were able to recover to their predisease state, and 9/20 of patients had residual memory impairment. In the high titer group, 3/11 of patients experienced recurrence, while there was no recurrence in the low titer group. There was no statistically significant difference in the neurological prognosis between the 2 groups at 3 months of discharge and follow-up (the number of patients whose modified Rankin Scale score≤2: 10/10 vs 8/9, P=0.474). Conclusions:Patients with high serum anti LGI1 antibody titers are more likely to develop intracerebral lesions. Higher antibody titers may be associated with a higher risk of disease recurrence. There was no significant correlation between serum antibody titers and neurological outcomes.

Evaluation of three alum-precipitated Aeromonas hydrophila vaccines administered to Labeo rohita, Cirrhinus mrigala and Ctenopharyngodon idella: immunokinetics, immersion challenge and histopathology / Avaliação de três vacinas de Aeromonas hydrophila precipitadas com alúmen administradas a Labeo rohita, Cirrhinus mrigala e Ctenopharyngodon idella: imunocinética, desafio de imersão e histopatologia

Abstract Aeromonas hydrophila is a cause of infectious disease outbreaks in carp species cultured in South Asian countries including Pakistan. This bacterium has gained resistance to a wide range of antibiotics and robust preventive measures are necessary to control its spread. No prior use of fish vaccines has been reported in Pakistan. The present study aims to develop and evaluate inactivated vaccines against local strain of A. hydrophila in Pakistan with alum-precipitate as adjuvant. The immunogenic potential of vaccine was evaluated in two Indian major carps (Rohu: Labeo rohita, Mori: Cirrhinus mrigala) and a Chinese carp (Grass carp: Ctenopharyngodon idella). Fish were vaccinated intraperitoneally followed by a challenge through immersion. Fish with an average age of 4-5 months were randomly distributed in three vaccinated groups with three vaccine concentrations of 108, 109 and 1010 colony forming unit (CFU)/ml and a control group. Fixed dose of 0.1ml was applied to each fish on 1st day and a booster dose at 15 days post-vaccination (DPV). Blood samples were collected on 14, 28, 35, 48 and 60 DPV to determine antibody titers in blood serum using compliment fixation test (CFT). Fish were challenged at 60 DPV with infectious A. hydrophila with 108 CFU/ml through immersion. Significantly higher levels of antibody titers were observed from 28 DPV in all vaccinated groups as compared to those in the control group. In challenge experiment the average RPS (relative percent survivability) was 71% for groups vaccinated with 109 and 1010 CFU/ml and 86% for 108 CFU/ml. Vaccine with 108 CFU/ml induced highest immune response followed by 109 and 1010 CFU/ml. The immune response of L. rohita and C. idella was better than that of C. mrigala. In general, normal histopathology was observed in different organs of vaccinated fish whereas minor deteriorative changes were found in fish vaccinated with higher concentrations of the vaccine.

Resumo Aeromonas hydrophila é uma causa de surtos de doenças infecciosas em espécies de carpas cultivadas em países do sul da Ásia, incluindo o Paquistão. Essa bactéria ganhou resistência a uma ampla gama de antibióticos, e medidas preventivas robustas são necessárias para controlar sua disseminação. Nenhum uso anterior de vacinas para peixes foi relatado no Paquistão. O presente estudo tem como objetivo desenvolver e avaliar vacinas inativadas contra cepa local de A. hydrophila no Paquistão com precipitado de alúmen como adjuvante. O potencial imunogênico da vacina foi avaliado em duas carpas principais indianas (Rohu: Labeo rohita, Mori: Cirrhinus mrigala) e uma carpa chinesa (Grass Carp: Ctenopharyngodon idella). Os peixes foram vacinados por via intraperitoneal, seguido de um desafio por imersão. Peixes com idade média de 4-5 meses foram distribuídos aleatoriamente em três grupos vacinados com três concentrações de vacina de 108, 109 e 1010 unidades formadoras de colônias (UFC) / ml e um grupo de controle. Foi aplicada dose fixa de 0,1ml em cada peixe no 1º dia e dose de reforço 15 dias pós-vacinação (DPV). Amostras de sangue foram coletadas em 14, 28, 35, 48 e 60 DPV para determinar os títulos de anticorpos no soro sanguíneo usando o teste de fixação de elogio (CFT). Os peixes foram desafiados a 60 DPV com infecciosa A. hydrophila com 108 CFU / ml por imersão. Níveis significativamente mais elevados de títulos de anticorpos foram observados em 28 DPV em todos os grupos vacinados, em comparação com aqueles no grupo de controle. Na experiência de desafio, o RPS médio (sobrevivência percentual relativa) foi de 71% para os grupos vacinados com 109 e 1010 CFU / ml e 86% para 108 CFU / ml. A vacina com 108 UFC / ml induziu a maior resposta imune seguida por 109 e 1010 UFC / ml. A resposta imune de L. rohita e C. idella foi melhor do que a de C. mrigala. Em geral, histopatologia normal foi observada em diferentes órgãos de peixes vacinados, enquanto pequenas alterações deteriorantes foram encontradas no grupo de controle e nos peixes vacinados com concentrações mais altas da vacina.

Development and verification of plaque method for detection of tick-borne encephalitis virus titer / 中国生物制品学杂志

@#Objective To develop and verify a plaque method for detection of infectious titer of tick-borne encephalitis virus(TBEV)strain(PHKT strain for short)adapted to primary hamster kidney(PHK)cells.Methods PHK cells were infected with TBEV,a primary mouse brain adaption strain,and passed consecutively for 12 passages.The titer of PHKT was detected by plaque method(Monolayer BHK-21 cells were infected with PHKT of various passages at different dilution ratios,and the plaque number was calculated by neutral red staining)and challenge titration in mouse brain(Mice were challenged with PHKT of various passages at different dilution ratios through brain cavity,0.03 mL for each,observed continuously for 14 days,and calculated for the median lethal dose(LD50)by Reed-Muench method)respectively,and the correlation between the results of two methods was analyzed.The developed plaque method for the detection of TBEV titer was verified for specificity,repeatability and intermediate precision.Results The plaque titer of PHKT virus was up to8.9 lgPFU/mL;The correlation between the results of plaque method and mouse brain challenge titration method was good(r = 0.92);The specificity of plaque method for detecting infectious titer of PHKT virus was good,and the coefficients of variation(CVs)of repeatability and intermediate precision were both less than 5%.Conclusion A plaque method for detecting infectious titer of PHKT virus was developed,which may be used as an alternative method for challenge titration in mouse brain.

Neutralization against SARS-CoV-2 Delta/Omicron variants and B cell response after inactivated vaccination among COVID-19 convalescents / 医学前沿

Emerging SARS-CoV-2 variants have made COVID-19 convalescents susceptible to re-infection and have raised concern about the efficacy of inactivated vaccination in neutralization against emerging variants and antigen-specific B cell response. To this end, a study on a long-term cohort of 208 participants who have recovered from COVID-19 was conducted, and the participants were followed up at 3.3 (Visit 1), 9.2 (Visit 2), and 18.5 (Visit 3) months after SARS-CoV-2 infection. They were classified into three groups (no-vaccination (n = 54), one-dose (n = 62), and two-dose (n = 92) groups) on the basis of the administration of inactivated vaccination. The neutralizing antibody (NAb) titers against the wild-type virus continued to decrease in the no-vaccination group, but they rose significantly in the one-dose and two-dose groups, with the highest NAb titers being observed in the two-dose group at Visit 3. The NAb titers against the Delta variant for the no-vaccination, one-dose, and two-dose groups decreased by 3.3, 1.9, and 2.3 folds relative to the wild-type virus, respectively, and those against the Omicron variant decreased by 7.0, 4.0, and 3.8 folds, respectively. Similarly, the responses of SARS-CoV-2 RBD-specific B cells and memory B cells were boosted by the second vaccine dose. Results showed that the convalescents benefited from the administration of the inactivated vaccine (one or two doses), which enhanced neutralization against highly mutated SARS-CoV-2 variants and memory B cell responses. Two doses of inactivated vaccine among COVID-19 convalescents are therefore recommended for the prevention of the COVID-19 pandemic, and vaccination guidelines and policies need to be updated.

Neutralization against SARS-CoV-2 Delta/Omicron variants and B cell response after inactivated vaccination among COVID-19 convalescents / 医学前沿

Emerging SARS-CoV-2 variants have made COVID-19 convalescents susceptible to re-infection and have raised concern about the efficacy of inactivated vaccination in neutralization against emerging variants and antigen-specific B cell response. To this end, a study on a long-term cohort of 208 participants who have recovered from COVID-19 was conducted, and the participants were followed up at 3.3 (Visit 1), 9.2 (Visit 2), and 18.5 (Visit 3) months after SARS-CoV-2 infection. They were classified into three groups (no-vaccination (n = 54), one-dose (n = 62), and two-dose (n = 92) groups) on the basis of the administration of inactivated vaccination. The neutralizing antibody (NAb) titers against the wild-type virus continued to decrease in the no-vaccination group, but they rose significantly in the one-dose and two-dose groups, with the highest NAb titers being observed in the two-dose group at Visit 3. The NAb titers against the Delta variant for the no-vaccination, one-dose, and two-dose groups decreased by 3.3, 1.9, and 2.3 folds relative to the wild-type virus, respectively, and those against the Omicron variant decreased by 7.0, 4.0, and 3.8 folds, respectively. Similarly, the responses of SARS-CoV-2 RBD-specific B cells and memory B cells were boosted by the second vaccine dose. Results showed that the convalescents benefited from the administration of the inactivated vaccine (one or two doses), which enhanced neutralization against highly mutated SARS-CoV-2 variants and memory B cell responses. Two doses of inactivated vaccine among COVID-19 convalescents are therefore recommended for the prevention of the COVID-19 pandemic, and vaccination guidelines and policies need to be updated.

Quantification of complete viral particles in inactivated avian influenza virus antigen by high performance size exclusion chromatography coupled with multi-angle laser light scattering / 生物工程学报

We developed a method for accurate quantification of the intact virus particles in inactivated avian influenza virus feedstocks. To address the problem of impurities interference in the detection of inactivated avian influenza virus feedstocks by direct high performance size exclusion chromatography (HPSEC), we firstly investigated polyethylene glycol (PEG) precipitation and ion exchange chromatography (IEC) for H5N8 antigen purification. Under the optimized conditions, the removal rate of impurity was 86.87% in IEC using DEAE FF, and the viral hemagglutination recovery was 100%. HPSEC was used to analyze the pretreated samples. The peak of 8.5-10.0 min, which was the characteristic adsorption of intact virus, was analyzed by SDS-PAGE and dynamic light scattering. It was almost free of impurities and the particle size was uniform with an average particle size of 127.7 nm. After adding antibody to the IEC pretreated samples for HPSEC detection, the characteristic peak disappeared, indicating that IEC pretreatment effectively removed the impurities. By coupling HPSEC with multi-angle laser scattering technique (MALLS), the amount of intact virus particles in the sample could be accurately quantified with a good linear relationship between the number of virus particles and the chromatographic peak area (R2=0.997). The established IEC pretreatment-HPSEC-MALLS assay was applied to accurate detection of the number of intact virus particles in viral feedstocks of different subtypes (H7N9), different batches and different concentrations, all with good applicability and reproducibility, Relative standard deviation < 5%, n=3.

Effect of multiple punctures on quality of inactivated poliomyelitis vaccine made from Sabin strains in 5-dose vial presentation / 中国生物制品学杂志

@#ObjectiveTo evaluate the effect of multiple punctures on the quality of inactivated poliomyelitis vaccine made from Sabin strains(sIPV)in 5-dose vials.MethodsPre-puncture samples were sampled by opening the cover from 3batches of sIPV stored for about 24 months and balanced at room temperature at least 20 min;The same three batches of sIPV were punctured for the first to fifth needle on the 0,7,14,21 and 28 d respectively,which were balanced at room temperature at least 20 min before each sampling. After sampling,the remaining samples were returned to 2～8 ℃ for preservation. According to the requirements of enterprise registration standard(YBS01052021),all the samples before and after the fifth needle puncture were tested,and the other 4 needle puncture samples were tested for pH,osmotic molar concentration,aseptic test,bacterial endotoxin,D antigen content of typeⅠ,Ⅱ and Ⅲ virus,appearance,abnormal toxicity,protein content and 2-phenoxyethanol content. The relative change rates of 2-phenoxyethanol content,protein content,osmotic molar concentration and D antigen content of typeⅠ,Ⅱ and Ⅲ virus were calculated. SPSS 20 software was used to analyze the relative change rate of each index by one-way ANOVA,and the effect of multiple punctures on the quality of sIPV was evaluated.ResultsThe result of each test item was in compliance with enterprise registration standard before and after each puncture. There was no significant difference between each puncture on the relative rate of change of 2-phenoxyethanol content,protein content,D-antigen content of typeⅡ and Ⅲ virus(F = 2. 125,1. 155,1. 137 and 1. 882,P = 0. 152,0. 386,0. 393and 0. 190,respectively);There was a significant difference in the relative change rate of osmotic molar concentration and Dantigen content of TypeⅠvirus(F = 4. 750 and 4. 010,P = 0. 021 and 0. 034,respectively). The result of Duncan test showed that compared with the first puncture,the relative change rate of osmotic molar concentration after the second and third puncture showed no significant difference,while that after the fourth puncture showed significant difference and a relatively stable result was observed after the fifth puncture. Regarding the relative rate of change of D-antigen content of TypeⅠvirus,there was no significant difference among the first,second,fourth and fifth punctures,while a significant difference existed between the third and the other four punctures.ConclusionFive punctures within 28 days had no effect on the quality of sIPV in 5-dose vials.