COMPARATIVE-ANALYSIS OF HUMORAL IMMUNE-RESPONSES TO HIV TYPE-1 ENVELOPE GLYCOPROTEINS IN MICE IMMUNIZED WITH A DNA VACCINE, RECOMBINANT SEMLIKI-FOREST-VIRUS RNA, OR RECOMBINANT SEMLIKI-FOREST-VIRUS PARTICLES

The Semliki Forest virus (SFV) system seems to be a useful new approac h for generating effective immune responses against HIV-1 in animal mo dels. We evaluated this system by comparing the humoral immune respons es raised in mice immunized against the HIV-1 envelope with the SFV sy stem, a DNA vaccine, and a recombinant Env glycoprotein, gp160 ELISA a ntibody titers (204,800) were highest in the sera from mice immunized with recombinant Semliki Forest virus particles. These sera contained antibodies to the CD4-binding site and recognized linear epitopes on g p120 and gp41 that were also recognized by a pool of sera from HIV-1-i nfected individuals, This demonstrates that the HIV-1 envelope produce d in vivo by the SFV system does not fold aberrantly, A low level of n eutralizing antibodies against the HIV-1(LAI) strain was also detected in the serum of one mouse immunized with recombinant SFV particles, s uggesting that booster injections should be given to achieve a more ef fective immune response. SFV recombinant particles induced the stronge st humoral responses to the HIV-1 envelope of all the potential HIV en v vaccines tested.