Improved NYVAC-Based Vaccine Vectors

Abstract

While as yet there is no vaccine against HIV/AIDS, the results of the phase III Thai trial (RV144) have been encouraging and suggest that further improvements of the prime/boost vaccine combination of a poxvirus and protein are needed. With this aim, in this investigation we have generated derivatives of the candidate vaccinia virus vaccine vector NYVAC with potentially improved functions. This has been achieved by the re-incorporation into the virus genome of two host range genes, K1L and C7L, in conjunction with the removal of the immunomodulatory viral molecule B19, an antagonist of type I interferon action. These novel virus vectors, referred to as NYVAC-C-KC and NYVAC-C-KC-ΔB19R, have acquired relevant biological characteristics, giving higher levels of antigen expression in infected cells, replication-competency in human keratinocytes and dermal fibroblasts, activation of selective host cell signal transduction pathways, and limited virus spread in tissues. Importantly, these replication-competent viruses have been demonstrated to maintain a highly attenuated phenotype.

Deletion of the Vaccinia Virus N2L Gene Encoding an Inhibitor of IRF3 Improves the Immunogenicity of Modified Vaccinia Virus Ankara Expressing HIV-1 Antigens

“…(81), but an additional fifth deletion of the uracil-DNA glycosylase gene (MVA101R) decreased the responses (81). Moreover, NYVAC vectors with a single deletion of a VACV gene encoding a TLR inhibitor (A46R [83]) and with single or double deletions in VACV genes encoding type I and II IFN binding proteins (B19R and B8R, respectively [84][85][86]) were also able to enhance the immune responses to HIV-1 antigens in mice.…”

Removal of Vaccinia Virus Genes That Block Interferon Type I and II Pathways Improves Adaptive and Memory Responses of the HIV/AIDS Vaccine Candidate NYVAC-C in Mice

“…One approach to improve the vector immunogenicity is to remove from the viral DNA genes that antagonize host-specific immune responses. This strategy has being successfully used for MVA and NYVAC vectors by targeting several immunomodulatory genes (8,10,15,16,24,42,47). Since virus recognition and induction of IFNs are critical components of the innate immune system, here we evaluated in a mouse model how the single or double deletion of the viral genes B8R and B19R affected the immunogenicity of the HIV/AIDS vaccine candidate NYVAC-C.…”

“…The plasmid transfer vector pGem-RG-B19R wm, used for the construction of the recombinant viruses NYVAC-C-⌬B19R and NYVAC-C-⌬B8R/⌬B19R with B19R deleted or with both B8R and B19R genes deleted, respectively, has been previously described (24).…”

“…We recently reported the generation and in vitro characterization of an improved NYVAC-C recombinant expressing the HIV-1 Env and Gag-Pol-Nef antigens from clade C, by deletion of the viral gene B19R (NYVAC-C-⌬B19R) (24,42). In contrast to the parental NYVAC-C, the deletion mutant NYVAC-C-⌬B19R induced in human DCs enhanced IFN-␣ production, maturation, and expression of IFN-induced pathways and IFN-regulated transcription factors as well as multiple inflammatory cytokines.…”

NFκB activation by modified vaccinia virus as a novel strategy to enhance neutrophil migration and HIV-specific T-cell responses

“…The plasmid transfer vectors pGem-RG-A52R-wm, pGem-RG-B15R-wm, and pGem-RG-K7R-wm, used for deletion of A52R, B15R, and K7R ORF from the NYVAC-C genome, respectively, were obtained by sequential cloning of A52R, B15R, and K7R recombination flanking sequences into the plasmid pGem-Red-GFP-wm as described (52). The plasmid transfer vector pCAR-2/K7R used for the insertion of the K7R gene was obtained by cloning the K7R sequence into the plasmid pCAR-2 (patent WO2007132052 A1).…”