Production and characterization of monoclonal antibodies to human immunodeficiency virus type 1 gp120 envelope glycoprotein

Monoclonal antibodies to human immunodeficiency virus type 1 envelope glycoprotein gp 120 (HIV-1 gp120) were produced and characterized. For immunogen, recombinant gp120 polypeptide expressed in bacteria was prepared and injected into mice. From two fusion experiments, twenty hybridomas secreting monoclonal antibodies against the recombinant gp120 were initially screened by immunodot blot analysis. Among the antibodies, 15 of them showed strong reactivities with the recombinant protein expressed in bacteria in Western blot and thus it was tested if these could react with the recombinant protein expressed in insect cells. All of the 15 antibodies immunostained the protein band with varing degrees of reactivities. Next, we tested whether the antibodies recognize authentic gp120 protein expressed in mammalian cells. COS-1 cells were transfected with the cDNA encoding gp120 protein, and the transiently expressed proteins were analyzed with the mAbs by Western blot analysis and immunofluorescence microscopy. Six of the monoclonal antibodies reacted with the protein band of authentic gp120 expressed in mammalian cells in the Western blot, and five stained the cell periphery of the transfected COS-1 cells in immunofluorescence. The mAbs described in this study should prove to be useful tools for the biochemical, immunological, and structural analysis of HIV-1 gp120 envelope glycoprotein.