A human cervical explant culture was utilized for the preclinical assessment of anti-human immunodeficiency virus type 1 (HIV-1) activity and tissue toxicity of formulated, candidate
topical microbicides. Products tested included
cellulose acetate 1,2-benzene dicarboxylate (CAP), a
carrageenan-based product (PC-515), a
naphthalene sulfonate
polymer (
PRO 2000), a
lysine dendrimer (
SPL7013), a nonnucleoside
reverse transcriptase inhibitor (
UC781), and an
antimicrobial peptide (
D2A21), along with their
placebos. Cervical explants were cultured overnight with HIV-1 with or without product, washed, and monitored for signs of HIV-1
infection. HIV-1
infection was determined by p24gag levels in the basolateral medium and by immunohistochemical analysis of the explant. Product toxicity was measured by the MTT [1-(4,5-dimethylthiazol-2-yl)-3,5-diphenylformazan] assay and histology. CAP,
PRO 2000,
SPL7013, and
UC781 consistently prevented HIV-1
infection in all explants tested. PC-515 and
D2A21 prevented HIV-1
infection in 50% or fewer of the explants tested.
Placebos did not prevent
infection in any of the explants tested. With the exception of
PRO 2000 (4%), the MTT assay and histological analysis of the other products and
placebos showed minimal toxicity to the epithelium and submucosa. Collectively, these data suggest that this culture system can be used for evaluating the safety and efficacy of
topical microbicides designed for vaginal use.