Self-assessment of COVID-19 vaccination efficacy using a simple POCT for SARS-CoV-2 S1 protein antibody IgG-IgM

BackgroundMore than ten novel COVID-19 vaccines have been approved with protections against SARS-CoV-2 infections ranges between 52-95%. It is of great interest to the vaccinees who have received the COVID-19 vaccines, vaccine developers and authorities to identify the non-responders in a timely manner so intervention can take place by either giving additional boosts of the same vaccine or switching to a different vaccine to improve the protection against the SARS-CoV-2 infections. A robust correlation was seen between binding antibody titer and efficacy (p=0.93) in the clinic studies of 7 COVID-19 vaccines, so it is of urgency to develop a simple POCT for vaccinees to self-assess their immune response at home. MethodsUsing CHO cell-expressed full length SARS-CoV2 S1 protein as coating antigen on colloidal gold particles, a SARS-CoV-2 S1 IgG-IgM antibody lateral flow test kit (POCT) was developed. The test was validated with negative human sera collected prior to the COVID-19 outbreaks, and blood samples from human subjects prior, during, and post-immunization of COVID-19 vaccines. ResultsThe specificity of the POCT was 99.0%, as examined against 947 normal human sera and 20 whole blood samples collected pre-immunization. The limit of detection was 50 IU/mL of pseudovirus neutralizing titer (PVNT) using human anti-SARS-2 neutralizing standards from convalescent sera. The sensitivity of POCT for SARS-CoV-2 S1 protein antibody IgG-IgM was compared with SARS-CoV-2 RBD antibody ELISA and determined to be 100% using 23 blood samples from vaccinated human subjects and 10 samples from non-vaccinated ones. Whole blood samples were collected from 119 human subjects (ages between 22-61 years) prior to, during, and post-vaccination of five different COVID-19 vaccines. Among them, 115 people tested positive for SARS-CoV-2 S1 antibodies (showing positive at least once) and 4 people tested negative (tested negative at least twice on different days), demonstrating 96.64% of seroconversion after full-vaccination. 92.3% (36/39) of the human subjects who were younger than 45 achieved seroconversion within 2 weeks while only 57.1% (4/7) of subjects older than 45 tested positive for S1 antibodies, suggesting that younger people develop protection much faster than older ones. Even though the S1 antibody level in 88% of human subjects vaccinated with inactivated virus dropped below 50 IU/mL two months later, one boost could quickly raise the S1 antibody titer above 50 IU/mL of PVNT, indicates that the initial vaccination was successful and immunization memory was developed. ConclusionUsing the lateral flow tests of SARS-CoV2 S1 IgG+IgM, vaccinated human subjects can easily self-assess the efficacy of their vaccination at home. The vaccine developer could quickly identify those non-responders and give them an additional boost to improve the efficacy of their vaccines. Vaccinees who failed in response could switch to different types of COVID-19 vaccines since there are more than 10 COVID-19 vaccines approved using three different platform technologies. HighlightsO_LIMore than ten novel COVID-19 vaccines have been approved with protections against SARS-CoV-2 infections ranges between 52-95%. It is of great interest to the vaccinees who have received the COVID-19 vaccines, vaccine developers and authorities to identify the non-responders in a timely manner. C_LIO_LIA highly specific and very simple lateral flow test kit for measurement of SARS-CoV-2 S1IgG+IgM antibodies post-immunization of COVID-19 vaccine using peripheral blood was developed as a home-test assay with a limit of detection (LOD) at 50 IU/mL of pseudovirus neutralizing titer (PVNT). C_LIO_LIAfter full vaccinations with COVID-19 vaccines, 96.6% of the volunteers successfully achieved the seroconversion of SARS-CoV-2 S1 IgG+IgM antibody. C_LIO_LI92.3% (36/39) of the human subjects who were younger than 45 achieved seroconversion within 2 weeks while only 57.1% (4/7) of subjects older than 45 tested positive for S1 antibodies, suggesting that younger people develop protection much faster than older ones. C_LIO_LIEven though the S1 antibody level in 88% of human subjects vaccinated with inactivated virus dropped below the detection 2-6 months later, one boost could quickly raise the S1 antibody titer above 50 IU/mL of PVNT, indicating that the initial vaccination was successful and immunization memory was developed. C_LI

Neutralization properties of different genotypes and mutants of severe fever with thrombocytopenia syndrome virus / 中华微生物学和免疫学杂志

Objective:To analyze the neutralization properties of different genotypes and mutants of severe fever with thrombocytopenia syndrome virus (SFTSV).Methods:Pseudoviruses of SFTSV of different genotypes and mutants were constructed using VSVΔG-Fluc*G backbone. Neutralization assays were established based on the pseudoviruses. DNA vaccines for different SFTSV genotypes were prepared. Serum samples were collected from guinea pigs immunized with the DNA vaccines. Neutralizing antibodies in serum samples from immunized guinea pigs and naturally infected patients were detected using neutralization assays and analyzed.Results:The pseudoviruses of five genotypes and 43 mutants were successfully constructed and the neutralization assays based the pseudoviruses were successfully established after optimizing the reaction parameters. The dilution multiple corresponding to the inhibition rate of neutralizing antibody to half of the pseudovirus infection was taken as the titer of neutralizing antibody by the reduction in pseudovirus reporter gene. The neutralization antibody titers in naturally infected patients and immunized guinea pigs were respectively in the ranges of 1∶100-1∶43 000 and 1∶100-1∶2 500 when detected with the reference HB29 pseudovirus. The neutralization antibody titers ranged from 1∶100-1∶2 500 after immunization with different genotypes of DNA vaccines. No significant statistical difference in neutralization antibody titer was observed among different genotypes or mutant strains.Conclusions:The neutralization properties of different genotypes and mutants showed no significant change, which would be very useful for developing vaccines.

Analysis of correlation between childhood abuse and adolescent psychological capital / 中国学校卫生

Objective@#To understand current situation and relations of childhood abuse and psychological capital, providing scientific basis for adolescent mental health promotion.@*Methods@#Stratified cluster sampling method was used to select 1 894 students from junior high schools and senior high schools in Harbin. Questionnaire survey was conducted by using Childhood Trauma QuestionnaireShort Form (CTQ-SF) and Positive Psychological Capital (PPQ).@*Results@#The total rate of childhood abuse among adolescents in the region was 98.3%. In addition to emotional abuse, scores of other dimensions of childhood abuse were higher for boys than for girls(P<0.01). Childhood abuse in rural area was higher than those in urban area except physical abuse(P<0.05). High psychological capital was observed among participants with boys higher in selfefficacy and resilience than that of girls(P<0.05). Psychological capital in urban students was higher than rural students(P<0.05). Except for the negative correlation between sexual abuse and resilience, all other dimensions of childhood abuse were negatively correlated with four dimensions of psychological capital. Stepwise regression analysis showed that emotional abuse, emotional neglect and physical neglect was negatively correlated with all dimensions of psychological capital(P<0.01); Sexual abuse showed negative association with selfefficacy and optimism(P<0.01).@*Conclusion@#Childhood abuse is closely related to psychological capital among adolescents in Harbin, suggesting exposure to childhood abuse might confer detrimental effects on psychological capital development.

Validation of a pseudovirus-based neutralization assay for detection of human papillomavirus antibodies in human serum samples / 中华微生物学和免疫学杂志

Objective@#To validate a pseudovirus-based neutralization assay for the detection of antibodies against human papillomavirus (HPV) in human serum samples.@*Methods@#The specificity, accuracy, precision, range of linearity, limit of detection and robustness of the neutralization assay were evaluated using HPV-negative serum samples, vaccinated serum samples with quadri-valent vaccine, and international standards for detecting antibodies against HPV16 and HPV18.@*Results@#Based on the data of the HPV-naïve samples, the criteria of positivity was determined as follows: the 50% inhibitory dose (ID50) of the tested sample was not less than 40 and 2-fold not less than that for bovine papillomavirus. The neutralization assay showed good accuracy with a recovery rate of 87%-122% and excellent reproducibility with intra- and inter-assay variation of 5%-27% and 10%-26% respectively. The HPV16 and HPV18 international standards were used to define the limit of quantification, which was 1.28 IU/ml for HPV16 and 0.96 IU/ml for HPV18. Acceptable ranges of variation for the key parameters of this assay were defined, which showed the good robustness of the pseudovirus-based neutralization assay.@*Conclusion@#The pseudovirus-based neutralization assay for the detection of HPV antibodies showed good specificity, accuracy, sensitivity, and robustness, suggesting that it could be used to evaluate the immunogenicity of HPV vaccines.

Genetic diversity of Liriope Muscari by TRAP analysis / 中国中药杂志

<p><b>OBJECTIVE</b>Target region amplification polymorphism (TRAP) marker was occupied to study on the genetic diversity of fifty Liriope Muscari clones.</p><p><b>METHOD</b>Total eight genes, one lectin gene and seven related to fructose, photosynthesis and steroid saponin metabolism, were selected as target genes and used to design thirteen the anchored primers for pairing with nineteen arbitrary primers. And eleven combinations of primers were screened to be able to produce clear banding patterns and polymorphisms.</p><p><b>RESULT</b>The results showed that 335 bands were amplified totally by 11 pair TRAP primers, of which 323 bands (96.41%) were polymorphic in the species level The average of polymorphism information content (PIC) was 0.930. gene differentiation index (Gst) was 0.610. The results of cluster analysis based on UPGMA revealed genetic coefficient ranged from 0.52 to 0.98.</p><p><b>CONCLUSION</b>A relatively high genetic diversity existed in L. muscari, a certain level of genetic differentiation among populations.</p>