Differences in p24 Ag production by Th1-polarized versus Th2-polarized naive T cells are due to differences in viral entry and not in cell proliferation.

Naive CD4⁺ T cells were activated with PHA and IL-2 in the presence of IL-12 (Th1-polarized) or IL-4 (Th2-polarized) and infected 3 days later with HIV-1IIIB (X4-tropic) or HIV-1BaL (R5-tropic). Parallel cultures were infected with recombinant HIV-1–CAT viruses containing HXBc2 or YU2 env proteins (X4-tropic and R5-tropic, respectively). SK-specific (Th1) and Der p 1–specific (Th2) T cell lines (Figure 1) were also infected with either HIV-1BaL, HIV-1IIIB, or HIV-1 strains YU2 or 1HXBc2. (A) Spontaneous p24 Ag release measured in supernatants of Th1-polarized (black columns) or Th2-polarized (white columns) cell cultures 4 days after infection with HIV-1IIIB or HIV-1BaL. (B) CAT activity in cell lysates from parallel cultures infected with X4-tropic or R5-tropic HIV-CAT viruses measured 4 days after infection, as described in “Materials and Methods.” (C) Numbers of viable (trypan blue negative) cells in Th1-polarized (black symbols) or Th2-polarized (white symbols) T-cell cultures from day 1 to day 4 after infection with HXBc2 (circles) or YU2 (squares) HIV-CAT viruses (left panel) and levels of ³H-thymidine uptake in the same culture (right panel). (D) Spontaneous p24 Ag release in supernatants of SK-specific (Th1; black bars) or Der p 1–specific (Th2; open bars) T cells 6 days after infection with HIV-1IIIB or HIV-1BaL. (E) CAT activity in cell lysates from a parallel culture infected with YU2 or HXBc2 HIV-1 strains. (F) Numbers of viable (trypan blue negative) cells in SK-polarized (black symbols) or Der p 1–polarized (white symbols) T-cell cultures from day 1 to day 4 after infection with HXBc2 (circles) or YU2 (squares) HIV-CAT viruses (left panel) and levels of ³H-thymidine uptake in the same culture (right panel). A representative experiment is shown.