Efficacy of postexposure prophylaxis after intravaginal exposure of pig-tailed macaques to a human-derived retrovirus (human immunodeficiency virus type 2)

Abstract

Postexposure prophylaxis (PEP) after intravaginal exposure to human immunodeficiency virus (HIV) was investigated using the HIV type 2 (HIV-2)/pig-tailed macaque transmission model. PEP for 28 days with the reverse transcriptase inhibitor (R)-9-(2-phosphonylmethoxypropyl)adenine (PMPA; tenofovir) was initiated 12 to 72 h following HIV-2 exposure. Systemic infection was not evident in the 12- and 36-h groups, as defined by plasma viremia, cell-associated provirus, antibody responses, and lymph node virus. Breakthrough infection in the 72-h group was detected at week 16 post-virus exposure. These results demonstrate for the first time using a vaginal transmission model that early intervention after high-risk sexual exposures may prevent infection.

Figures

FIG. 1

HIV-2 load in plasma and CVL specimens through 24 weeks after intravaginal virus exposure in untreated control macaques (n = 4). Plasma vRNA levels are reported as log10 copies per milliliter and virus levels in CVL supernatants are indicated as log10 total copies per lavage specimen. The sensitivity limits are 100 copies/ml for plasma and 400 total copies for CVL supernatants with a 50-μl sample equivalent input into the assay system (dashed line).

FIG. 2

Longitudinal HIV-2 vRNA levels in plasma versus CVL supernatants after intravaginal virus exposure in experimental macaque groups (n = 4 each) receiving PEP with PMPA at the indicated times. Results are reported as in Fig. 1.