Western blot analysis of HIV-1 Gag protein expressed in Vero cells by rMuVgag and rVSVN4CT1gag1. Replicate Vero cell monolayers in six-well plates were infected at an MOI of 5 PFU/cell with either rMuVgag or rVSVN4CT1gag1. Cell lysates were collected at 24 h and 48 h postinfection. The Gag protein was detected with an HIV-1 Gag-specific monoclonal antibody. Lanes 1, uninfected cells; lanes 2, rMuV-infected cells; lanes 3, rMuVgag-infected cells; lanes 4, rVSV-infected cells; lanes 5, rVSVN4CT1gag1-infected cells. Protein molecular mass markers (shown in kDa) flank each gel.