HIV GP120-SPECIFIC CELL-MEDIATED IMMUNE-RESPONSES IN MICE AFTER ORAL IMMUNIZATION WITH RECOMBINANT SALMONELLA

Salmonella is of great interest as a potential human immunodeficiency virus vaccine vector because of its ability to elicit potent mucosal a nd systemic immune responses when administered orally. To determine wh ether such a vaccine could elicit an immune response in mice, plasmids expressing HIV gp120-LAI were introduced into attenuated S. typhimuri um. Three serial doses of 10(10) recombinant organisms were administer ed orally to BALB/c mice at 2-week intervals. Immunized mice but not c ontrol mice demonstrated proliferative T cell responses to gp120-LAI, comparable in magnitude to the proliferative responses to Salmonella a ntigens. Immunized mice had detectable serum and intestinal Salmonella -specific IgA and serum Salmonella-specific IgG. However, no gp120-spe cific antibody was detected in either serum or intestinal washes. Thes e results indicate that live recombinant Salmonella-based vaccine cons tructs can induce HIV-specific cellular immune responses in vivo.