INVESTIGATION OF THE COMPLEMENT RECEPTOR-3 (CD11B CD18) IN HUMAN RECTAL EPITHELIUM/

Rectal and cervicovaginal mucosa are common routes of transmission of HIV, although the mechanism of transmission is unknown. We have invest igated human rectal and cervicovaginal epithelia for the expression of complement receptors (CR) and cell adhesion molecules which may be in volved in HIV and other infections. In rectal mucosa, CR3 was detected in the surface and crypt epithelial cells by immunohistology, using M oAbs to CD18 and CD11b in 10 out of 15 specimens. RNA transcripts enco ding both CD11b and CD18 were also demonstrated in surface and crypt e pithelial cells by in situ hybridization. Although CD11b was detected in the epithelial cells in three out of the 14 cervicovaginal specimen s, we were unable to detect CD18. We suggest that expression of the CD 11b/CD18 heterodimer might facilitate transmission of HIV by enhancing binding of HIV-antibody complexes in seminal fluid to epithelial cell s. Alternatively, since intercellular adhesion molecule-1 (ICAM-1) is a receptor for CD11b/CD18, this may promote adhesion between epithelia l cells and HIV-infected mononuclear cells in seminal fluid.