Hsp70 coimmunoprecipitates with Vpr from HIV-1– infected cells. Macrophages were infected with macrophage-tropic HIV-1 strain ADA or mock infected. At 48 hours after infection, cells were lysed and the lysates were immunoprecipitated with a polyclonal anti-Hsp70 antibody. Cell lysates and immunoprecipitates were analyzed by Western blotting for the presence of p24 (A), Hsp70 (B), and Vpr (C). In one sample (mock + sVpr), synthetic Vpr²⁶  was added to mock-infected cell lysate prior to immunoprecipitation. WB indicates Western blot; IP, immunoprecipitation.