FIG.6.

SPR analysis of CHO cell-expressed HIV-1_JR-FL SOS gp140, gp140_UNC, and gp120 proteins. Anti-gp120 and anti-gp41 MAbs were immobilized onto sensor chips and exposed to buffers containing the indicated gp120 or gp140 glycoproteins in either purified or unpurified form, as indicated. Where noted, Env proteins were mixed with an eightfold molar excess of sCD4 for 1 h prior to analysis. Culture supernatants from stably transfected CHO cells were used as the source of unpurified SOS gp140 and gp140_UNC proteins. The concentrations of these proteins were measured by Western blotting and adjusted so that approximately equal amounts of each protein were loaded. Only the binding phases of the sensorgrams are shown; in general, the dissociation rates were too slow to provide meaningful information.