Broad-spectrum vaccine via combined immunization routes triggers potent immunity to SARS-CoV-2 and its variants.

IMPORTANCE: The development of broad-spectrum SARS-CoV-2 vaccines will reduce the global economic and public health stress from the COVID-19 pandemic. The use of conserved T-cell epitopes in combination with spike antigen that induce humoral and cellular immune responses simultaneously may be a promising strategy to further enhance the broad spectrum of COVID-19 vaccine candidates. Moreover, this research suggests that the combined vaccination strategies have the ability to induce both effective systemic and mucosal immunity, which may represent promising strategies for maximizing the protective efficacy of respiratory virus vaccines.

Early and Long-Term HIV-1 Immunogenicity Induced in Macaques by the Combined Administration of DNA, NYVAC and Env Protein-Based Vaccine Candidates: The AUP512 Study.

To control HIV infection there is a need for vaccines to induce broad, potent and long-term B and T cell immune responses. With the objective to accelerate and maintain the induction of substantial levels of HIV-1 Env-specific antibodies and, at the same time, to enhance balanced CD4 and CD8 T cell responses, we evaluated the effect of concurrent administration of MF59-adjuvanted Env protein together with DNA or NYVAC vectors at priming to establish if early administration of Env leads to early induction of antibody responses. The primary goal was to assess the immunogenicity endpoint at week 26. Secondary endpoints were (i) to determine the quality of responses with regard to RV144 correlates of protection and (ii) to explore a potential impact of two late boosts. In this study, five different prime/boost vaccination regimens were tested in rhesus macaques. Animals received priming immunizations with either NYVAC or DNA alone or in combination with Env protein, followed by NYVAC + protein or DNA + protein boosts. All regimens induced broad, polyfunctional and well-balanced CD4 and CD8 T cell responses, with DNA-primed regimens eliciting higher response rates and magnitudes than NYVAC-primed regimens. Very high plasma binding IgG titers including V1/V2 specific antibodies, modest antibody-dependent cellular cytotoxicity (ADCC) and moderate neutralization activity were observed. Of note, early administration of the MF59-adjuvanted Env protein in parallel with DNA priming leads to more rapid elicitation of humoral responses, without negatively affecting the cellular responses, while responses were rapidly boosted after repeated immunizations, indicating the induction of a robust memory response. In conclusion, our findings support the use of the Env protein component during priming in the context of an heterologous immunization regimen with a DNA and/or NYVAC vector as an optimized immunization protocol against HIV infection.

Combined immunization with inactivated vaccine reduces the dose of live B. abortus A19 vaccine.

BACKGROUND: Brucella spp. is an important zoonotic pathogen responsible for brucellosis in humans and animals. Brucella abortus A19 strain is a widespread vaccine in China. However, it has a drawback of residual virulence in animals and humans. METHODS: In this study, the BALB/c mice were inoculated with either 100 µL PBS(control group, C group), 109 CFU/mL inactivated B. abortus A19 strain (I group), 105 CFU/mL (low-dose group, L group) 106 CFU/mL live B. abortus A19 strain (high-dose group, H group), or 105 CFU/mL live B. abortus A19 strain combined with 109 CFU/mL inactivated B. abortus A19 strain (LI group). Mice were challenged with B. abortus strain 2308 at 7 week post vaccination. Subsequently, the immune and protective efficacy of the vaccines were evaluated by measuring splenic bacterial burden, spleen weight, serum IgG, interferon-gamma (IFN-γ), interleukin-4 (IL-4) percentage of CD4 + and CD8 + T cells of mice via bacterial isolation, weighing, ELISA and flow cytometry, respectively. RESULTS: The splenic bacterial burden and spleen weight of the mice in group LI were mostly equivalent to the mice of group H. Moreover, Brucella-specific serum IgG, IFN-γ, IL-4, and the percentage of CD4+ and CD8+ T cells of the LI group mice were similar to those of the H group. In the subsequent challenge test, both vaccines conferred protective immunity to wild-type (WT) 2308 strain. In addition, the levels of IL-4 and IFN-γ, CD4+ and CD8+ T cells in these mice were similar to those of the mice in the H group. CONCLUSIONS: Combined immunization with low dose live vaccine and inactivated vaccine allowed to reduce the live B. abortus A19 vaccine, dose with an equivalent protection of the high-dose live vaccine.

A potential role of macrophage phenotypes in the early evaluation of the effects of combined Yersinia Pestis and Brucella bovis vaccine immunization / 国际药学研究杂志

Objective In emergency situations where simultaneous immunization by multiple vaccines are required,how to rapidly evaluate the effect of combined immunization is an urgent issue that needs to be solved.This study aimed to investigate the po-tential role and application value of the phenotypic changes of macrophages in rapid evaluation of the effect of combined Yersinia pestis and Brucella bovis vaccine immunization at early stage.Methods Y.pestis and B.bovis vaccines were injected into mice alone or in combination to establish animal models.The changes of the macrophage phenotypes(M1 or M2 polarization)and the CD8+T cell pheno-types and functions were detected in the early(4 d)and the late(14 d)stage of the immunization,respectively.The effect of the immuno-phenotype of macrophages at early stage on the function of CD8+T cells at late stage was analyzed.Results The co-immunization by Y.pestis and B.bovis vaccines led to the attenuation of the M1-polarization of macrophages at early stage,which were marked by de-creased expression of CD16/32 and increased expression of Detectin-1 on cell surface as well as decreased expression of IL-12 and in-creased expression of IL-4 inside the macrophage,in comparison with single vaccine groups,suggesting an interference between the two vaccines.Meanwhile,the activity of CD8+T cells(including the ratio of CD8+CD69+T,CD8+IFN-γ+T and CD8+GranzymeB+T cells) in combined immunization group showed similar tendency to the attenuated phenotypic M1-polarization of macrophages. Conclusion The phenotype of macrophages at the early stage of the co-immunization by Y.pestis and B.bovis vaccines showed consistency with the phenotype and function of CD8+T cells at late stage.It might give us some hint about the possibility of utilizing the phenotypic changes of macrophages to rapidly evaluate the effect of the co-immunization at early stage.

Analysis on the maternal HBsAg carrying rate and the neonatal immunization in Huangpu District of Shanghai / 上海预防医学

Objective To understand the maternal positive rate of HBsAg and the neonatal immunization in Huangpu District of Shanghai so as to provide bases for developing strategies of preventing hepatitis B and reducing the rate of neonatal hepatitis B virus infection.Methods By adopting cluster sampling research methods, retrospective surveys were conducted for the detection of HBsAg of the pregnant women from all the obstetric institutions(7 institutions) in Huangpu District of Shanghai as well as for the neonatal hepatitis B vaccinations therein from 2013 to 2015, and statistical analyses were made for the results thereof by utilizing the SPSS 20.0 software.Results A total of 29 425 pregnant women were surveyed and the positive rate of HBsAg thereof was 3.95%.The detection rate of HBsAg(98.42% & 96.76%) as well as the positive rate of HBsAg (2.58% & 4.50%) for both the local and external pregnant women in Shanghai, respectively, showed statistical differences (P<0.01).The newborns of mothers with positive rates of HBsAg who used combined immunization(HBIG+hepatitis B vaccine) amounted to 1 130, with the rate of combined immunization reaching 98.52%.Conclusion The positive rate of HBsAg for the pregnant women in Huangpu District of Shanghai is below the level thereof for those in either the whole country or the other cities and provinces, which shows that Shanghai has made effective achievements in hepatitis B vaccination as well as in the health education relevant thereto.However, active and positive combined immunization measures should still be strengthened for the newbornsof mothers with positive rates of HBsAg.In addition, with the growth of pregnant women under new policies, better maternal health care mechanism should be established and various prenatal inspections should be well implemented, thus reducing the rate of the people without taking the detection of HBsAg and preventing newborns from being infected by hepatitis B virus as a result of failing to take timely immunization measures.

The humoral immune response in guinea pigs primed with recombinant vaccinia virus strains ex-pressing Transmitted/Founder virus HIV-1 membrane proteins and boosted with gp140 protein / 中华微生物学和免疫学杂志

Objective To analyze the antibody responses in guinea pigs vaccinated with recombi-nant vaccinia virus( rTT) strains expressing transmitted/founder ( T/F) HIV-1 membrane proteins in combi-nation with gp140 protein.Methods Guinea pigs were primed with rTT strains and boosted twice with gp140 protein in every four weeks.Serum samples were collected from guinea pigs before immunization and in 2, 6 and 10 weeks after the last immunization for the detection of HIV-1-specific binding antibodies, neu-tralizingantibodiesandtherelativeavidityofantibodies.Results (1)Thebindingantibodiesspecificto HIV-1 B′/C, B, AE subtypes were efficiently induced by the immunization of rTT-B, rTT-C and rTT-CON vaccinia strains in combination with gp140 protein.The antibody titers ranged from 111 430 to 1 024 000. More antibodies against HIV-1 B′/C and AE subtypes were induced in guinea pigs by the immunization of rTT-C and rTT-CON strains in combination with gp140 protein than those by using rTT-B strain prime-protein boost strategy (P<0.05).No significant differences with the titers of HIV-1 B subtype specific antibody were observed among the guinea pigs immunized with the three strategies.( 2 ) High titers of SF162 and ZM109 neutralizing antibodies were induced in guinea pigs immunized with rTT-B, rTT-C and rTT-CON vac-cinia strains in combination with gp140 protein, ranging from 83.76 to 649.30.No significant differences were found among the three groups.(3) The HIV-1 V1V2-gp70 specific antibodies associated with protec-tive immunity were induced by immunization of the three virus prime-protein boost strategies.No significant differences were observed among them.(4) Antibodies induced in guinea pigs by immunization of the three strategies showed strong affinity to membrane proteins of HIV-1 B′/C, B, AE subtype strains.No significant differences were found among the three immunization strategies.Conclusion A strong humoral immune re-sponse was induced in guinea pigs primed with recombinant vaccinia virus strains expressing T/F virus HIV-1 membrane proteins and boosted with gp140 protein.