Figure 3.
Early acquisition of Salmonella Typhimurium (STm)–specific CD4+ T-cell immune responses. Percentage are shown for STm-specific CD4+ T cells producing total (A; n = 68), early (B; n = 36), and late (C; n = 32) cytokine and phorbol 12-myristate 13-acetate (PMA)/ionomycin stimulated CD4+ T cells producing total cytokine (D; n = 62). Nonlinear polynomial regression models of third order were fit to data relating specific T-cell cytokine response to age. STm-specific T cells response within early and late periods was determined by linear regression, represented by solid central lines; dashed lines represent 95% confidence intervals.