TRYPTASE-TL2 IN THE MEMBRANE OF HUMAN LYMPHOCYTES-T4+ IS A NOVEL BINDING-PROTEIN OF THE V3 DOMAIN OF HIV-1 ENVELOPE GLYCOPROTEIN-GP120

A novel membrane-bound serine esterase in cultured human T4+ lymphocytes, recently purified and named tryptase TL2, binds specifically to the external envelope protein gp120 of HIV-1, interacting with its V3 domain. This binding was selectively blocked by inhibitors of tryptase TL2 with a GPCR sequence in their reactive site, synthetic peptides corresponding with the sequences of the V3 domains of various HIV-1 strains with the GPGR sequence, and antibody against tryptase TL2, or neutralizing antibody against the V3 domain of HTLV-III(B). These findings suggest that tryptase TL2 is a binding protein of the V3 domain of HIV-1 envelope glycoprotein.