Presence of cytotoxic granules in CD4⁺ T lymphocytes from LTNP-100149. (A) Flow cytometry histograms, gated on CD3⁺CD4⁺ lymphocytes, show production of IFN-γ by TIA-1⁺ CD4⁺ T cells in response to p24, peptide no. 42, and peptide no. 106 in ICC. (B) Flow cytometry histograms, gated on CD3⁺CD4⁺ lymphocytes, show proliferation of CFSE-labeled TIA-1⁺ CD4⁺ T cells in response to p24, peptide no. 42, and peptide no. 106. Results are representative of at least 3 experiments over 9 months. (C) TEM showing morphology of granules within some vesicles in purified CD4⁺ T cells from LTNP-100149. Magnification × 74 000.