Evidence that membrane proteins of rhabdomyosarcoma cell line RD bind human immunodeficiency virus type 1 (HIV-1).

Membrane proteins (MP) obtained from the human mesenchymal rhabdomyosarcoma cell line RD were coated on 96-well polystyrene microplates and tested for their ability to bind human immunodeficiency virus type 1 (HIV-1). The virus bound to MP was detected by solid phase assay. Anti-human CD4 monoclonal antibodies directed against the HIV-1 gp120 binding site of the CD4 receptor did not inhibit viral binding to MP. HIV-1 specific polypeptides were recovered from coated MP to microplates by a modification of the solid phase immunoisolation technique and shown by immunoblotting analysis using a high titer of biotinylated human anti-HIV-1 IgG. Together these findings provide evidence that HIV-1 binding to RD cell surfaces can proceed via a mechanism other than those mediated by the CD4 receptor.