HIV-1 INFECTION OF IN-VITRO CULTURED HUMAN MONOCYTES - EARLY EVENTS AND INFLUENCE OF ANTI HIV-1 ANTIBODIES

To characterize the role of the humoral immune response on HIV-1 infec tion of monocytes and macrophages (M phi s) we examined the susceptibi lity of in vitro cultured monocyte/M phi s to various HIV-1 isolates a nd the influence of heterologous and particularly autologous anti HIV- 1 sera on this infection. Depending on the period of in vitro cultivat ion and the virus isolate used different patterns of susceptibility we re detected. One week old monocyte/M phi s were highly susceptible to HIV-1 infection, in contrast to monocyte/M phi s cultured 4 weeks. The infection by virus isolated immediately after seroconversion lead to persistent infection with high level of antigen production in contrast to infection by homologous virus isolated later. MAb against the V3-I IIB loop and sCD4 inhibited the infection of monocyte/M phi s in a dos e dependent manner, indicating that infection requires binding to CD4 and that post binding events may be common to the infection of lymphoc ytes. Anti HIV-1 sera showed neutralizing activity against heterologou s and even autologous escape virus. This finding, together with the ob servation that monocytes and M phi s are infected in vivo, suggests th at protection against HIV-1 infection of monocytes and M phi s in vivo may not be obtainable by the humoral immune response alone.