RESUMO
There is a great need for the development of vaccines that induce potent and long-lasting protective immunity against SARS-CoV-2. Multimeric display of the antigen combined with potent adjuvant can enhance the potency and longevity of the antibody response. The receptor binding domain (RBD) of the spike protein is a primary target of neutralizing antibodies. Here, we developed a trimeric form of the RBD and show that it induces a potent neutralizing antibody response against live virus with diverse effector functions and provides protection against SARS-CoV-2 challenge in mice and rhesus macaques. The trimeric form induces higher neutralizing antibody titer compared to monomer with as low as 1µg antigen dose. In mice, adjuvanting the protein with a TLR7/8 agonist formulation alum-3M-052 induces 100-fold higher neutralizing antibody titer and superior protection from infection compared to alum. SARS-CoV-2 infection causes significant loss of innate cells and pathology in the lung, and vaccination protects from changes in innate cells and lung pathology. These results demonstrate RBD trimer protein as a suitable candidate for vaccine against SARS-CoV-2.
Assuntos
Adjuvantes Imunológicos/administração & dosagem , Vacinas contra COVID-19/imunologia , COVID-19/imunologia , COVID-19/prevenção & controle , Compostos Heterocíclicos com 3 Anéis/administração & dosagem , Ácidos Esteáricos/administração & dosagem , Compostos de Alúmen/administração & dosagem , Enzima de Conversão de Angiotensina 2/imunologia , Enzima de Conversão de Angiotensina 2/metabolismo , Animais , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Formação de Anticorpos/imunologia , Vacinas contra COVID-19/administração & dosagem , Modelos Animais de Doenças , Compostos Heterocíclicos com 3 Anéis/imunologia , Humanos , Macaca mulatta , Camundongos , Ligação Proteica , SARS-CoV-2/isolamento & purificação , Glicoproteína da Espícula de Coronavírus/imunologia , Ácidos Esteáricos/imunologiaRESUMO
To increase vaccine immunogenicity, modern vaccines incorporate adjuvants, which serve to enhance immune cross-protection, improve humoral and cell-mediated immunity, and promote antigen dose sparing. Pattern recognition receptors (PRRs), including the Toll-like receptor (TLR) family are promising targets for development of agonist formulations for use as vaccine adjuvants. Combinations of co-delivered TLR4 and TLR7/8 ligands have been demonstrated to have synergistic effects on innate and adaptive immune response. Here, we create liposomes that stably co-encapsulate CRX-601, a synthetic TLR4 agonist, and UM-3004, a lipidated TLR7/8 agonist, within the liposomal bilayer in order to achieve co-delivery, allow tunable physical properties, and induce in vitro and in vivo immune synergy. Co-encapsulation demonstrates a synergistic increase in IL-12p70 cytokine output in vitro from treated human peripheral blood mononuclear cells (hPBMCs). Further, co-encapsulated formulations give significant improvement of early IgG2a antibody titers in BALB/c mice following primary vaccination when compared to single agonist or dual agonists delivered in separate liposomes. This work demonstrates that co-encapsulation of TLR4 and lipidated TLR7/8 agonists within the liposomal bilayer leads to innate and adaptive immune synergy which biases a Th1 immune response. Thus, liposomal co-encapsulation may be a useful and flexible tool for vaccine adjuvant formulation containing multiple TLR agonists.
Assuntos
Adjuvantes Imunológicos/administração & dosagem , Compostos Heterocíclicos com 3 Anéis/administração & dosagem , Imunidade Humoral/imunologia , Monossacarídeos/administração & dosagem , Vacinas/administração & dosagem , Animais , Sistemas de Liberação de Medicamentos , Sinergismo Farmacológico , Feminino , Compostos Heterocíclicos com 3 Anéis/imunologia , Compostos Heterocíclicos com 3 Anéis/farmacologia , Humanos , Leucócitos Mononucleares/imunologia , Lipossomos , Camundongos , Camundongos Endogâmicos BALB C , Monossacarídeos/imunologia , Monossacarídeos/farmacologia , Células Th1/imunologia , Receptor 4 Toll-Like/agonistas , Receptor 7 Toll-Like/agonistas , Receptor 8 Toll-Like/agonistas , Vacinas/imunologiaRESUMO
Antibodies and cytotoxic T cells represent 2 arms of host defense against pathogens. We hypothesized that vaccines that induce both high-magnitude CD8+ T cell responses and antibody responses might confer enhanced protection against HIV. To test this hypothesis, we immunized 3 groups of nonhuman primates: (a) Group 1, which includes sequential immunization regimen involving heterologous viral vectors (HVVs) comprising vesicular stomatitis virus, vaccinia virus, and adenovirus serotype 5-expressing SIVmac239 Gag; (b) Group 2, which includes immunization with a clade C HIV-1 envelope (Env) gp140 protein adjuvanted with nanoparticles containing a TLR7/8 agonist (3M-052); and (c) Group 3, which includes a combination of both regimens. Immunization with HVVs induced very high-magnitude Gag-specific CD8+ T cell responses in blood and tissue-resident CD8+ memory T cells in vaginal mucosa. Immunization with 3M-052 adjuvanted Env protein induced robust and persistent antibody responses and long-lasting innate responses. Despite similar antibody titers in Groups 2 and 3, there was enhanced protection in the younger animals in Group 3, against intravaginal infection with a heterologous SHIV strain. This protection correlated with the magnitude of the serum and vaginal Env-specific antibody titers on the day of challenge. Thus, vaccination strategies that induce both CD8+ T cell and antibody responses can confer enhanced protection against infection.