HIV gp120 receptors on human dendritic cells

Dendritic cells (DCs) are important targets for human immunodeficiency viru s (HIV) because of their roles during transmission and also maintenance of immune competence. Furthermore, DCs are a key cell in the development of HI V vaccines. In both these settings the mechanism of binding of the HIV enve lope protein gp120 to DCs is of importance. Recently a single C-type lectin receptor (CLR), DC-SIGN, has been reported to be the predominant receptor on monocyte-derived DCs (MD-DCs) rather than CD4. In this study a novel bio tinylated gp120 assay was used to determine whether CLR or CD4 were predomi nant receptors on MDDCs and ex vivo blood DCs. CLR bound more than 80% of g p120 on MDDCs, with residual binding attributable to CD4, reconfirming that CLRs were the major receptors for gp120 on MDDCs. However, in contrast to recent reports, gp120 binding to at least 3 CLRs was observed: DC-SIGN, man nose receptor, and unidentified trypsin resistant CLR(s). In marked contras t, freshly isolated and cultured CD11c(+ve) and CD11c(-ve) blood DCs only b ound gp120 via CD4. In view of these marked differences between MDDCs and b lood DCs, HIV capture by DCs and transfer mechanisms to T cells as well as potential antigenic processing pathways will need to be determined for each DC phenotype. (Blood. 2001;98:2482-2488) (C) 2001 by The American Society of Hematology.