F4 + AS01

**F4 + AS01** is an investigational therapeutic HIV-1 vaccine candidate consisting of a recombinant fusion protein F4, which combines four HIV-1 clade B antigens (Gag p17, Gag p24, reverse transcriptase from Pol, and Nef), adjuvanted with AS01. AS01 is a liposome-based adjuvant system containing MPL (a TLR4 agonist, 3-O-desacyl-4’-monophosphoryl lipid A) and QS-21 (a saponin), which synergistically enhance innate immunity by inducing early IFNγ production from NK cells and CD8+ T cells via IL-12/IL-18 from subcapsular sinus macrophages, leading to dendritic cell activation and robust Th1-biased CD4+ T-cell responses alongside antibodies. Developed by GlaxoSmithKline (GSK), it demonstrated safety, tolerability, and potent, long-lasting polyfunctional HIV-specific CD4+ T-cell responses in phase I/II trials in HIV-seronegative and ART-experienced individuals, with optimal immunogenicity at the 10 μg F4 dose.

Other names

GSK Biologicals HIV Vaccine 732462F4 vaccineF-4 vaccineF 4 vaccine