BINDING OF HUMAN-IMMUNODEFICIENCY-VIRUS TYPE-1 (HIV-I) TO PARTIALLY PURIFIED MEMBRANE-VESICLES OF LYMPHOBLASTOID CELL-LINE CEM

Binding of human immunodeficiency virus type 1 (HIV-1) to membrane of its. target cells was studied by a quantitative and non-isotopic metho d called the viral membrane trapping method (VMTM). Membranes prepared from the CD4 positive lymphoblastoid cell line CEM and adsorbed to a solid support retained the ability to bind HIV-1. Similar results were obtained by Western dot blot and ELISA modification of VMTM, when mem brane fraction was bound to nitrocellulose or polystyrene, respectivel y. In ELISA modification, viral association with 1 mu g of membranes c oated on 96-well microplate was linear within a range of 3.75 mu g to 60 mu g of p24(gag) protein. The use of anti-CD4 mAbs, OKT4A. and 13B8 .2, identified CD4 molecule as a major HIV-1 binding component of memb rane fraction. The procedure will allow the study of virus binding to this and to other possible additional receptor(s).