Compare Neutralizing Antibody Responses To Ebola-GP In Different Immunization Models Of Chinese Rhesus Macaques

Humoral immune response,effective antibody or B-cell response is one of the most important immune responses of the body to fight against virus or other pathogen infections.We compare neutralizing antibody responses to Ebola-GP in three immunization models of Chinese rhesus macaques,and studied the mechanisms of broadly neutralizing antibody response.Explaining the correlation between immune response and the protective and durable of vaccines.To extend the theory to the development of other virus infection,such as influenza and AIDS vaccines.Humoral immune response and generating high affinity neutralizing antibodies were performing in germinal center.To elucidate the correlation between immune response and the protective and durable of vaccines.In this study,referring to the response time of the germinal center,we design three immunization strategies.We utilize the full-length gene of Ebola virus glycoprotein(Ebola-GP)as DNA immunogen,and Ebola virus glycoprotein ectodomains as protein immunogen to immunize Chinese rhesus macaques.Through the dynamic tracking of multiple time points over a long period,comparing neutralizing antibody response to three difference immunization strategies.Exploring the correlation between immune response and the protective and durable of vaccines.Part Ⅰ Immunization of Chinese rhesus macaques with Ebola-GP for neutralizing antibodiesObjective:In this study,we investigated the bingding activity and neutralizing capability of broadly protective antibodies of immunized Chinese rhesus macaques with Ebola-GP.Methods:We perform three immunization strategies:Group1 were performed conventional trivalent immunization,group2 were performed sequential immunization,and group3 were performed germinal-center-reaction-guided sequential immunization.All of the groups were immunized three times,every 6 weeks interval.Blood and Inguinal lymph nodes were collected at difference times pionts.The bingding activity and neutralizing capability of broadly antibodies are detected by ELISA and Neutralization assay.Results:1.Anti-GP 1.Antibodies of immunized Chinese rhesus macaques could combine with Zaire,Sudan,Bundibugyo GP.2.Antibodies of immunized Chinese rhesus macaques could neutralize the pseudoviruses of Zaire,Sudan,Bundibugyo.3.Conventional trivalent immunization strategies obtained the optimal antibody titers.Conclusion:Three The three Ebola-GP immunization strategies induced effective antibody immune responses with broadly neutralizing antibodies in Chinese rhesus macaques,thus providing a candidate for Ebola virus vaccine.Part Ⅱ Analysis of germinal center reactions in Ebola-GP immunized Chinese rhesus macaquesObjective:In this study,we investigated the germinal center(GC)reactions,including T follicular helper cells(Tfh),GC B cells,and memory B cells in Ebola-GP immunized Chinese rhesus macaques.Methods:The expression levels of Ki67,and Bcl-6 were examined by immunohistochemistry of inguinal lymph nodes.GC B cells frequencies and GC Tth cells frequencies in inguinal lymph node were analyzed by FCM.Memory B cells(MBCs)frequencies and plasma cells frequencies in peripheral blood were detected by FCM.The results were compared among animals received three immunization strategies.Results:The Ki-67 and Bcl-6 immunohistochemistry revealed the germinal centers with rapid cell proliferation and GC B cells differentiation.GC Tfh and B cells frequencies in the lymph nodes were signifificantly higher than baseline values after the third immunization.MBCs and PCs frequencies after the third immunization were signifificantly higher than before post-immunization.However,plasma cells frequencies were mildly higher than before post-immunization.Conclusion:In summary,the GC Tfh and B cells frequencies of lymph nodes were correlated with the antibody titers,indicating the immunogenicity of the vaccine.MBCs and plasma cells frequencies of perpheal blood,indicating that the vaccine induces the body to generate immunological memory.The immunized rhesus macaques with conventional multivalent immunization and germinal center reaction guided sequential immunization provide the possibility of screening broadly neutralizing antibodies against Ebola virus,which is of potentically significance for clinic.