BG505 MD39.3 mRNA

BG505 MD39.3 mRNA is an investigational mRNA-based HIV vaccine candidate designed to induce immune responses against HIV-1 by encoding a stabilized, native-like trimeric form of the HIV envelope (Env) spike protein, specifically derived from the BG505 strain and engineered as "MD39.3" for enhanced stability and immunogenicity[5][1][2]. The vaccine delivers messenger RNA that instructs host cells to produce this Env trimer, which is then recognized by the immune system to elicit neutralizing antibodies targeting the virus’s entry mechanism[1][7]. It is being evaluated in Phase 1 clinical trials for safety and immunogenicity in healthy adults without HIV infection[2][4]. The vaccine cannot cause HIV infection as it does not contain live or infectious virus[8].