Dendritic cells and macrophages in HIV-infected patients may hinder antigen presentation.

(A) Binding of HIV-1 gp120 to DC-SIGN on DCs enhances infection of CD4 T cells and may interfere with their activation. (B) Macrophages from HIV-infected patients have reduced expression of molecules required for effective stimulation of T cells and have increased expression of molecules that can trigger apoptosis. Macrophages with defective APC function are not necessarily infected with HIV. The size of the labels in this figure reflects the relative expression level on macrophages from healthy donors and HIV-infected donors. Part B modified from Shearer71 copyright 1998 and reprinted with permission from Elsevier Science.