FIG. 6.

Combination of Tyr mutation and cytoplasmic domain truncation enhances induction of CD4 T-cell responses. Mouse splenocytes from each group were pooled, and the pooled splenocyte aliquots (2 × 10⁶ per well in 48-well plate) were stimulated for 16 h with each of the peptide pools covering the entire HIV 89.6 Env protein, followed by addition of brefeldin A, a further incubation of 5 h, and then staining for surface CD4 (PerCP) and CD8 (PE) and intracellular IFN-γ (APC). Numbers in lower right boxes represent percentages of IFN-γ-producing CD 4 T cells gated as shown in Fig. 4A. Peptide pools are 20-mers overlapping by 10 amino acids. Pool 1, amino acids 1 to 210; pool 2, amino acids 200 to 410; pool 3, amino acids 400 to 610; pool 4, amino acids 600 to 853.