Dendritic Cells Express and Use Multiple HIV Coreceptors

Abstract

Dendritic cells (DC) are the first immunocompetent cells to encounter antigen at areas of inflammation in mucous membranes¹, which are the major sites where the initiation of HIV infection occurs. HIV enters a mucous membrane and interacts with Langerhans cells (LC)/DC resulting in binding of the virus to the cell with or without infection. The cell then migrates and delivers virus to the paracortical region of the draining lymphoid tissue: LC/DC also provide activation stimuli to CD4⁺ T cells which become infected leading to replication and spread of virus^2,3. Recently, in vivo data in the macaque model have clarified certain pathogenic events associated with primary simian immunodeficiency virus (SIV) infection. SIV was placed in the vaginal vault and infected cells were then identified and followed using in situ PCR technology. DC in the lamina propria of the cervicovaginal mucosa were found to contain SIV DNA 2 days after exposure to virus. Infected cells were observed in the sub-capsular and paracortical regions of the draining lymph nodes; this series of events mirrors the course that DCs take upon receiving a signal to migrate from the tissues to lymphoid organs⁴. Thus, in an animal model of HIV, DC appeared to be responsible for bringing virus from the site of inoculation to the paracortical T cell regions of the draining lymphoid organs leading to viral replication and systemic spread of infection.