Prophylactic and therapeutic effect of AZT/3TC in RT-SHIV infected Chinese-origin rhesus macaques

BACKGROUND: The precise efficacy of nucleoside analogue reverse-transcriptase inhibitors (NRTIs) in preventing and inhibiting virus replication remains unknown in RT-SHIV infected Chinese-origin rhesus macaques (Ch RM). FINDINGS: Ch RM were inoculated intravenously with 200 TCID(50) RT-SHIV and treated by gavage with NRTIs (20 mg AZT and 10 mg 3TC twice per day) for four consecutive weeks beginning at one hour, on day 217 or 297 post inoculation, respectively. Treatment with AZT/3TC inhibited transiently RT-SHIV replication during chronic infection, but did not significantly affect peripheral blood CD4(+) T cells in macaques. Treatment with AZT/3TC at 1 hour post infection prevented RT-SHIV infection in two out of four animals during the 120-day observation period. CONCLUSIONS: Therefore, the Ch RM model with RT-SHIV infection can be used to evaluate the efficacy of new NRTIs.