CELLULAR TARGETS OF INFECTION AND ROUTE OF VIRAL DISSEMINATION AFTER AN INTRAVAGINAL INOCULATION OF SIMIAN IMMUNODEFICIENCY VIRUS INTO RHESUS MACAQUES

We used the simian immunodeficiency virus (SIV)/rhesus macaque model t o study events that underlie sexual transmission of human immunodefici ency virus type 1 (HIV-1). Four female rhesus macaques were inoculated intravaginally with SIVmac251, and then killed 2, 5, 7, and 9 d later . A technique that detected polymerase chain reaction-amplified SIV in situ showed that the first cellular targets for SIV were in the lamin a propria of the cervicovaginal mucosa, immediately subjacent to the e pithelium. Phenotypic and localization studies demonstrated that many of the infected cells were likely to be dendritic cells. Within 2 d of inoculation, infected cells were identified in the paracortex and sub capsular sinus of the draining internal iliac lymph nodes. Subsequentl y, systemic dissemination of SIV was rapid, since culturable virus was detectable in the blood by day 5. From these results, we present a mo del for mucosal transmission of SIV and HIV-1.