Expression of activation markers on PBLs after infection with OKT3SU-displaying HIV-1– or MLV-derived vectors.

The percentage of PBLs that stained positive for the activation markers CD25 (top) and CD69 (bottom) was determined by FACS analysis for the freshly isolated PBLs (0 hour) and at different time points after infection with the HIV-1–derived (left) and the MLV-derived vectors (right) generated with the indicated glycoproteins. The data, shown here for PBLs of set 7 (Figures 5-8 present the results of transduction), are representative of other experiments. VSV-G–pseudotyped vectors were used to infect freshly isolated PBLs in the presence of 1 μg indicated soluble antibody. PBLs were also stained for the CD71 activation marker (data not shown). The proportion of CD71⁺ cells was less than 12% for PBLs incubated with VSV-G–pseudotyped vectors, in the absence of anti-CD3 or anti-CD28 antibodies, and was higher than 80% for PBLs incubated either with VSV-G–pseudotyped virions in the presence of anti-CD3 and anti-CD28 antibodies or with OKT3SU/OKT3SUx-displaying vector particles.