FIG 6.

There are no significant differences between SIVmac239 and SIVmac239 N173Q sgp120 binding to human CD4. (A) Coomassie blue-stained SDS-PAGE gel of SIVmac239 and SIVmac239 N173Q sgp120 expressed in and purified from transfected 293F cells. (B) Co-IP of sgp120 with human CD4-Ig. (C) Kinetic analysis of the interactions between sgp120 and human sCD4. Direct binding was measured by Biacore assays. (D) The N173 mutation does not significantly affect CD4-Ig binding to Env trimers in a cell-based ELISA. Results shown are CD4-Ig binding after normalization by SIVmac251 antiserum binding.