INFECTION OF HUMAN FETAL ASTROCYTES WITH HIV-1 - VIRAL TROPISM AND THE ROLE OF CELL-TO-CELL CONTACT IN VIRAL TRANSMISSION

Astrocyte cultures from human fetal brain were infected with human imm unodeficiency virus (HIV) either as free virus or with a chronically i nfected lymphoblastoid cell line and monitored for signs of infection. The lymphocytotropic strains HIV3B and HIVSF2(ARV-2) but not the mono cytotropic strain HIVAda-M infected the human fetal astrocytes. The in fected cells were monitored by immunocytochemistry, detection of p24 a ntigen in the supernatants and polymerase chain reaction amplification of the proviral DNA. No morphological or cytopathic effects were seen in these cells. Upon co-curture of astrocytes with a lymphoblastoid c ell line chronically infected with HIVSF2(ARV-2), the lymphoblastoid c ells readily adhered to the astrocytes as determined by a Cr-51 adhesi on assay and by light and electron microscopy. This cell to cell conta ct resulted in infection of increased numbers of astrocytes. Similar a dhesion of lymphoblasts to microglia was not seen. Thus, astrocytes fr om human fetal brain can be infected in vitro directly by lymphocytotr opic strains of HIV or by adherence to infected lymphoblastoid cells.