FIG. 8.

Induction of cytokine and chemokine gene expression is dependent on the affinity of HIV-1 binding to CD4 receptor. (A) The levels of gp120 envelope in pelleted virion preparations (10⁸ RT cpm) of NL4-3 and NL4-3-derived clones NL-D368E and NL-D368P were determined by Western blot analysis using mouse anti-gp120 monoclonal antibodies. (B) Binding of NL4-3 but not NL-D368E and NL-D368P (45) induced expression of cytokine and chemokine genes in Jurkat cells. Purified virions (10⁸ RT cpm) were incubated for 3 h at 37°C, total RNA was isolated, and expression of cytokine and chemokine genes was analyzed by RT-PCR as described in the legend to Fig. 2. GAPDH served as an internal control.