Figure 1: Major types of human, mucosal, professional APC that serve as targets for primary HIV-1 infection in the mucosa. Expression of the CXCR4 coreceptor can occur after DC activation in vivo and in vitro culture. *Note that dDC and idDC are undergoing continuous revision (hence the markers in parentheses) and could represent a continuum of a single type of DC regulated by local environmental influences. CD103 = integrin alpha 3; CD141 = blood dendritic cell antigen 3; CD163 = scavenger receptor.