CD40L-adjuvanted DNA/modified vaccinia virus Ankara simian immunodeficiency virus SIV239 vaccine enhances SIV-specific humoral and cellular immunity and improves protection against a heterologous SIVE660 mucosal challenge.

It remains a challenge to develop a successful human immunodeficiency virus (HIV) vaccine that is capable of preventing infection. Here, we utilized the benefits of CD40L, a costimulatory molecule that can stimulate both dendritic cells (DCs) and B cells, as an adjuvant for our simian immunodeficiency virus (SIV) DNA vaccine in rhesus macaques. We coexpressed the CD40L with our DNA/SIV vaccine such that the CD40L is anchored on the membrane of SIV virus-like particle (VLP). These CD40L containing SIV VLPs showed enhanced activation of DCs in vitro. We then tested the potential of DNA/SIV-CD40L vaccine to adjuvant the DNA prime of a DNA/modified vaccinia virus Ankara (MVA) vaccine in rhesus macaques. Our results demonstrated that the CD40L adjuvant enhanced the functional quality of anti-Env antibody response and breadth of anti-SIV CD8 and CD4 T cell responses, significantly delayed the acquisition of heterologous mucosal SIV infection, and improved viral control. Notably, the CD40L adjuvant enhanced the control of viral replication in the gut at the site of challenge that was associated with lower mucosal CD8 immune activation, one of the strong predictors of disease progression. Collectively, our results highlight the benefits of CD40L adjuvant for enhancing antiviral humoral and cellular immunity, leading to enhanced protection against a pathogenic SIV. A single adjuvant that enhances both humoral and cellular immunity is rare and thus underlines the importance and practicality of CD40L as an adjuvant for vaccines against infectious diseases, including HIV-1. Despite many advances in the field of AIDS research, an effective AIDS vaccine that can prevent infection remains elusive. CD40L is a key stimulator of dendritic cells and B cells and can therefore enhance T cell and antibody responses, but its overly potent nature can lead to adverse effects unless used in small doses. In order to modulate local expression of CD40L at relatively lower levels, we expressed CD40L in a membrane-bound form, along with SIV antigens, in a nucleic acid (DNA) vector. We tested the immunogenicity and efficacy of the CD40L-adjuvanted vaccine in macaques using a heterologous mucosal SIV infection. The CD40L-adjuvanted vaccine enhanced the functional quality of anti-Env antibody response and breadth of anti-SIV T cell responses and improved protection. These results demonstrate that VLP-membrane-bound CD40L serves as a novel adjuvant for an HIV vaccine.

Kwa S ，Lai L ，Gangadhara S ，Siddiqui M ，Pillai VB ，Labranche C ，Yu T ，Moss B ，Montefiori DC ，Robinson HL ，Kozlowski PA ，Amara RR ... -  《-》

Virus-Like Particles Displaying Trimeric Simian Immunodeficiency Virus (SIV) Envelope gp160 Enhance the Breadth of DNA/Modified Vaccinia Virus Ankara SIV Vaccine-Induced Antibody Responses in Rhesus Macaques.

The encouraging results of the RV144 vaccine trial have spurred interest in poxvirus prime-protein boost human immunodeficiency virus (HIV) vaccine modalities as a strategy to induce protective immunity. Because vaccine-induced protective immunity is critically determined by HIV envelope (Env) conformation, significant efforts are directed toward generating soluble trimeric Env immunogens that assume native structures. Using the simian immunodeficiency virus (SIV)-macaque model, we tested the immunogenicity and efficacy of sequential immunizations with DNA (D), modified vaccinia virus Ankara (MVA) (M), and protein immunogens, all expressing virus-like particles (VLPs) displaying membrane-anchored trimeric Env. A single VLP protein boost displaying trimeric gp160 adjuvanted with nanoparticle-encapsulated Toll-like receptor 4/7/8 (TLR4/7/8) agonists, administered 44 weeks after the second MVA immunization, induced up to a 3-fold increase in Env-specific IgG binding titers in serum and mucosa. Importantly, the VLP protein boost increased binding antibody against scaffolded V1V2, antibody-dependent phagocytic activity against VLP-coated beads, and antibody breadth and neutralizing antibody titers against homologous and heterologous tier 1 SIVs. Following 5 weekly intrarectal SIVmac251 challenges, two of seven DNA/MVA and VLP (DM+VLP)-vaccinated animals were completely protected compared to productive infection in all seven DM-vaccinated animals. Vaccinated animals demonstrated stronger acute viral pulldown than controls, but a trend for higher acute viremia was observed in the DM+VLP group, likely due to a slower recall of Gag-specific CD8 T cells. Our findings support immunization with VLPs containing trimeric Env as a strategy to augment protective antibody but underscore the need for optimal engagement of CD8 T cells to achieve robust early viral control. The development of an effective HIV vaccine remains a global necessity for preventing HIV infection and reducing the burden of AIDS. While this goal represents a formidable challenge, the modest efficacy of the RV144 trial indicates that multicomponent vaccination regimens that elicit both cellular and humoral immune responses can prevent HIV infection in humans. However, whether protein immunizations synergize with DNA prime-viral vector boosts to enhance cellular and humoral immune responses remains poorly understood. We addressed this question in a nonhuman primate model, and our findings show benefit for sequential protein immunization combined with a potent adjuvant in boosting antibody titers induced by a preceding DNA/MVA immunization. This promising strategy can be further developed to enhance neutralizing antibody responses and boost CD8 T cells to provide robust protection and viral control.

Iyer SS ，Gangadhara S ，Victor B ，Shen X ，Chen X ，Nabi R ，Kasturi SP ，Sabula MJ ，Labranche CC ，Reddy PB ，Tomaras GD ，Montefiori DC ，Moss B ，Spearman P ，Pulendran B ，Kozlowski PA ，Amara RR ... -  《-》

CD40L-adjuvanted DNA/modified vaccinia virus Ankara simian immunodeficiency virus (SIV) vaccine enhances protection against neutralization-resistant mucosal SIV infection.

Here, we show that a CD40L-adjuvanted DNA/modified vaccinia virus Ankara (MVA) simian immunodeficiency virus (SIV) vaccine enhances protection against a pathogenic neutralization-resistant mucosal SIV infection, improves long-term viral control, and prevents AIDS. Analyses of serum IgG antibodies to linear peptides of SIV Env revealed a strong response to V2, with targeting of fewer epitopes in the immunodominant region of gp41 (gp41-ID) and the V1 region as a correlate for enhanced protection. Greater expansion of antiviral CD8 T cells in the gut correlated with long-term viral control.

Kwa S ，Sadagopal S ，Shen X ，Hong JJ ，Gangadhara S ，Basu R ，Victor B ，Iyer SS ，LaBranche CC ，Montefiori DC ，Tomaras GD ，Villinger F ，Moss B ，Kozlowski PA ，Amara RR ... -  《-》

Adjuvanting a Simian Immunodeficiency Virus Vaccine with Toll-Like Receptor Ligands Encapsulated in Nanoparticles Induces Persistent Antibody Responses and Enhanced Protection in TRIM5α Restrictive Macaques.

Our previous work has shown that antigens adjuvanted with ligands specific for Toll-like receptor 4 (TLR4) and TLR7/8 encapsulated in poly(lactic-co-glycolic) acid (PLGA)-based nanoparticles (NPs) induce robust and durable immune responses in mice and macaques. We investigated the efficacy of these NP adjuvants in inducing protective immunity against simian immunodeficiency virus (SIV). Rhesus macaques (RMs) were immunized with NPs containing TLR4 and TLR7/8 agonists mixed with soluble recombinant SIVmac239-derived envelope (Env) gp140 and Gag p55 (protein) or with virus-like particles (VLPs) containing SIVmac239 Env and Gag. NP-adjuvanted vaccines induced robust innate responses, antigen-specific antibody responses of a greater magnitude and persistence, and enhanced plasmablast responses compared to those achieved with alum-adjuvanted vaccines. NP-adjuvanted vaccines induced antigen-specific, long-lived plasma cells (LLPCs), which persisted in the bone marrow for several months after vaccination. NP-adjuvanted vaccines induced immune responses that were associated with enhanced protection against repeated low-dose, intravaginal challenges with heterologous SIVsmE660 in animals that carried TRIM5α restrictive alleles. The protection induced by immunization with protein-NP correlated with the prechallenge titers of Env-specific IgG antibodies in serum and vaginal secretions. However, no such correlate was apparent for immunization with VLP-NP or alum as the adjuvant. Transcriptional profiling of peripheral blood mononuclear cells isolated within the first few hours to days after primary vaccination revealed that NP-adjuvanted vaccines induced a molecular signature similar to that induced by the live attenuated yellow fever viral vaccine. This systems approach identified early blood transcriptional signatures that correlate with Env-specific antibody responses in vaginal secretions and protection against infection. These results demonstrate the adjuvanticity of the NP adjuvant in inducing persistent and protective antibody responses against SIV in RMs with implications for the design of vaccines against human immunodeficiency virus (HIV). The results of the RV144 HIV vaccine trial, which demonstrated a rapid waning of protective immunity with time, have underscored the need to develop strategies to enhance the durability of protective immune responses. Our recent work in mice has highlighted the capacity of nanoparticle-encapsulated TLR ligands (NP) to induce potent and durable antibody responses that last a lifetime in mice. In the present study, we evaluated the ability of these NP adjuvants to promote robust and durable protective immune responses against SIV in nonhuman primates. Our results demonstrate that immunization of rhesus macaques with NP adjuvants mixed with soluble SIV Env or a virus-like particle form of Env (VLP) induces potent and durable Env-specific antibody responses in the serum and in vaginal secretions. These responses were superior to those induced by alum adjuvant, and they resulted in enhanced protection against a low-dose intravaginal challenge with a heterologous strain of SIV in animals with TRIM5a restrictive alleles. These results highlight the potential for such NP TLR L adjuvants in promoting robust and durable antibody responses against HIV in the next generation of HIV immunogens currently being developed.

Kasturi SP ，Kozlowski PA ，Nakaya HI ，Burger MC ，Russo P ，Pham M ，Kovalenkov Y ，Silveira ELV ，Havenar-Daughton C ，Burton SL ，Kilgore KM ，Johnson MJ ，Nabi R ，Legere T ，Sher ZJ ，Chen X ，Amara RR ，Hunter E ，Bosinger SE ，Spearman P ，Crotty S ，Villinger F ，Derdeyn CA ，Wrammert J ，Pulendran B ... -  《-》

Preexisting vaccinia virus immunity decreases SIV-specific cellular immunity but does not diminish humoral immunity and efficacy of a DNA/MVA vaccine.

Kannanganat S ，Nigam P ，Velu V ，Earl PL ，Lai L ，Chennareddi L ，Lawson B ，Wilson RL ，Montefiori DC ，Kozlowski PA ，Moss B ，Robinson HL ，Amara RR ... -  《-》