Human CD40L⁺ CD8⁺ T cells express helper cytokines but not cytolytic molecules. (A) CD8⁺ and CD4⁺CD45RA⁻ memory T-cell subsets were sorted after 6-hour P/I stimulation and messenger RNA expression of cytokine genes was analyzed with microarrays. (B) CD8⁺ T cells were stimulated with P/I and were analyzed for CD40L expression and coexpression of cytokines using an intracellular cytokine assay. (C) CD8⁺ T cells were stimulated and analyzed for CD40L and degranulation (CD107a⁺) as well as for coexpression of perforin and granzyme B. (B-C) One representative experiment out of 5 is shown.