Expression of HIV-1 gp120 and human soluble CD4 by recombinant baculoviruses and their interaction in vitro.

The soluble domains of the envelope glycoprotein of HIV-1 (gp120) and human CD4 (sCD4) have been individually expressed in insect cells using recombinant baculoviruses. Each product is secreted from infected cells and accumulates in the surrounding media to levels of 1-2 mg/liter of 2 x 10(9) cells. Both molecules have full biological activity, and conditioned media from infected cells have been used to establish a simple assay for gp120-sCD4 interaction that is highly specific and amenable to mass screening. The crystallization of sCD4 purified from this source is reported.