CHARACTERIZATION OF A NOVEL BINDING-SITE FOR THE HUMAN-IMMUNODEFICIENCY-VIRUS TYPE-1 ENVELOPE PROTEIN GP120 ON HUMAN FETAL ASTROCYTES

I-125-labeled recombinant gp120 bound to primary cultures of human fetal astrocytes,vith a single class of 260-kDa binding sites, with a K-d of 26 nM and maximal number of binding sites of 29.9 fmol/4 x 10(4) cells. Neither CD4 nor galactocerebroside was detectable on astrocytes, and I-125-labeled recombinant gp120 binding to astrocytes was not blocked by antibodies against galactocerebroside or the gp120 binding domain of CD4.