FIG. 4.

Antibodies to integrin receptors block transduction of human cells. NIH 3T3 (A) and A375 human melanoma (B) cells were pretreated with polyclonal antibodies to β₁, β₃, and α_ν integrin receptors (Santa Cruz Biotechnology), infected with RGD₂₁-1, RGD₂₁-4, or RGD₂₁-9 viruses, and transduction was analyzed as described in the legend to Fig. 1. The three antibodies were diluted 1:100 in Dulbecco modified Eagle medium and incubated with cells for 4 h. Cells were then incubated with pseudotyped virus for 6 h.