Recombinant C. crescentus bacteria expressing Griffithsin, GB virus C E2 protein, elafin, α-1-antitrypsin, indolicidin, and the fusion inhibitor T-1249 were able to protect 40 to 75% of the BLT mice from vaginal infection with HIV-1JR-CSF, with C. crescentus bacteria expressing Griffithsin being the most effective. This evidence concerns the gene PI3 and infective vaginitis.