
Keywords: Aging; Immune function; Infection; Nutrition; 25-(OH)D; 25-hydroxyvitamin D; 1,25-(OH)2D; 1,25-dihydroxyvitamin D; APC; antigen-presenting cell; CI; confidence interval; Con A; concanavalin A; COX-2; cyclooxygenase-2; DC; dendritic cells; DTH; delayed-typ