[Elucidation of virus-host interaction using animal models towards vaccine development]

HIV replication highly interacts with host immunity resulting in life-long persistent virus replication in the presence of adaptive immune responses. Development of an effective vaccine is a key for control of global HIV epidemic, but immunization methods to induce effective anti-HIV immune responses have not been established. We have been focusing on analyzing virus-host immune interaction in vivo using animal models and applying findings to the development of vaccines. We have developed a novel immunogen selectively inducing virus-specific CD8+ T-cell responses and showed protective efficacy of vaccines against intrarectal SIV challenge. We have also worked on antibody responses, and determined the polymorphism in germline immunoglobulin genes in macaques and its association with induction of a particular class of anti-SIV neutralizing antibody. We applied the knowledge in HIV research to HTLV and COVID-19, showing protective efficacy of vaccine-induced neutralizing antibody against HTLV infection and viral suppression by vaccine-induced CD8+ T-cell responses against SARS-CoV-2 in macaque models.