New developments in a South African HIV vaccine trial

HIV life cycle – Russell Kightley Media

Subtype C gp140 Vaccine Boosts Immune Responses Primed by the South African AIDS Vaccine Initiative DNA-C2 and MVA-C HIV Vaccines after More than a 2-Year Gap

A phase I safety and immunogenicity study investigated South African AIDS Vaccine Initiative (SAAVI) HIV-1 subtype C (HIV-1C) DNA vaccine encoding Gag-RT-Tat-Nef and gp150, boosted with modified vaccinia Ankara (MVA) expressing matched antigens. Following the finding of partial protective efficacy in the RV144 HIV vaccine efficacy trial, a protein boost with HIV-1 subtype C V2-deleted gp140 with MF59 was added to the regimen. A total of 48 participants (12 U.S. participants and 36 Republic of South Africa [RSA] participants) were randomized to receive 3 intramuscular (i.m.) doses of SAAVI DNA-C2 of 4 mg (months 0, 1, and 2) and 2 i.m. doses of SAAVI MVA-C of 1.45 × 109 PFU (months 4 and 5) (n = 40) or of a placebo (n = 8). Approximately 2 years after vaccination, 27 participants were rerandomized to receive gp140/MF59 at 100 μg or placebo, as 2 i.m. injections, 3 months apart. The vaccine regimen was safe and well tolerated. After the DNA-MVA regimen, CD4+ T-cell and CD8+ T-cell responses occurred in 74% and 32% of the participants, respectively. The protein boost increased CD4+ T-cell responses to 87% of the subjects. All participants developed tier 1 HIV-1C neutralizing antibody responses as well as durable Env binding antibodies that recognized linear V3 and C5 peptides. The HIV-1 subtype C DNA-MVA vaccine regimen showed promising cellular immunogenicity. Boosting with gp140/MF59 enhanced levels of binding and neutralizing antibodies as well as CD4+ T-cell responses to HIV-1 envelope. (This study has been registered at ClinicalTrials.gov under registration no. NCT00574600 and NCT01423825.)

This is a pretty big deal – because it reports an extension of a wholly South African-originated vaccine trial, that consisted of a DNA prime with a subtype C gp150 gene and an artificial Gag-RT-Tat-Nef polyprotein gene, followed by a rMVA boost, that was as immunogenic as anything else trialled around the same time.

And development of which was shut down for political reasons in 2009, but that is old news….

This new development, where a subtype C gp140 (soluble form of Env) was given with MF59 adjuvant to trial participants 2 years after the initial vaccinations, showed that recall responses were strong – in both cellular and humoral arms of the immune system. Moreover, neutralising Ab were elicited.

This is a very promising development in the saga of HIV vaccinology, and it is to be hoped that further trials will be funded.

And both my sister-in-law and my wife are involved B-) What can I say, we’re a virological family!

This entry was posted on 7 June, 2016 at 08:55 and is filed under biotechnology, Evolution, General Virology, GMOs, HIV, Vaccines: General, Viruses. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.

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