FIG. 2.

PR⁺ and PR⁻ virions incorporate comparable levels of gp41. Virion lysates, prepared from concentrated virus stocks as described in the legend of Fig. 1, were transferred to polyvinylidene difluoride membranes and immunoblotted with the anti-gp41 MAb T32 (upper panel) and AIDS patient serum (lower panel) to detect p24 (capsid) and/or Pr55^Gag. To confirm equal loading of virion-associated material, blots were reprobed with an anti-Vpr antibody (data not shown). Quantitative Western blotting was performed with a Fluor-S MAX MultiImager (Bio-Rad, Hercules, Calif.). T32 was obtained from P. Earl (14), and AIDS patient serum was obtained from the National Institutes of Health AIDS Research and Reference Reagent Program. The data shown are representative of the results of at least five independent experiments.