Interleukin-1- and Type I Interferon-Dependent Enhanced Immunogenicity of an NYVAC-HIV-1 Env-Gag-Pol-Nef Vaccine Vector with Dual Deletions of Type I and Type II Interferon-Binding Proteins. Homo sapiens

NYVAC, a highly attenuated, replication-restricted poxvirus, is a safe and immunogenic vaccine vector. Deletion of immune evasion genes from the poxvirus genome is an attractive strategy for improving the immunogenic properties of poxviruses. Using systems biology approaches, we describe herein the enhanced immunological profile of NYVAC vectors expressing the HIV-1 clade C env, gag, pol, and nef genes (NYVAC-C) with single or double deletions of genes encoding type I (B19R) or type II (B8R) interferon (IFN)-binding proteins. Transcriptomic analyses of human monocytes infected with NYVAC-C, NYVAC-C with the B19R deletion (NYVAC-C- B19R), or NYVAC-C with B8R and B19R deletions (NYVAC-C- B8RB19R) revealed a concerted upregulation of innate immune pathways (IFN-stimulated genes [ISGs]) of increasing magnitude with NYVAC-C- B19R and NYVAC-C- B8RB19R than with NYVAC-C. Deletion of B8R and B19R resulted in an enhanced activation of IRF3, IRF7, and STAT1 and the robust production of type I IFNs and of ISGs, whose expression was inhibited by anti-type I IFN antibodies. Interestingly, NYVAC-C- B8RB19R induced the production of much higher levels of proinflammatory cytokines (tumor necrosis factor [TNF-], interleukin-6 [IL-6], and IL-8) than NYVAC-C or NYVAC-C- B19R as well as a strong inflammasome response (caspase-1 and IL-1 ) in infected monocytes. Top network analyses showed that this broad response mediated by the deletion of B8R and B19R was organized around two upregulated gene expression nodes (TNF and IRF7). Consistent with these findings, monocytes infected with NYVAC-C- B8RB19R induced a stronger type I IFN-dependent and IL-1-dependent allogeneic CD4 T cell response than monocytes infected with NYVAC-C or NYVAC-C- B19R. Dual deletion of type I and type II IFN immune evasion genes in NYVAC markedly enhanced its immunogenic properties via its induction of the increased expression of type I IFNs and IL-1 and make it an attractive candidate HIV vaccine vector. Overall design: Primary Human monocytes from 5 donors were incubated with each following vectors nyvacdb, nyvadb19r, nyvaccdb8rb19r_6h, untreated control and collected at 6h.