SYSTEMIC IMMUNE CHANGES FOLLOWING MEAL INTAKE IN HUMANS

Food intake represents a high intestinal antigen exposition requiring host defense. Besides local immune activation, this defense includes a coordinate systemic immune response, which may serve to support local immunity. This study examined influences of a standardized high-prote in meal on peripheral blood mononuclear cell counts; on the in vitro m itogen-stimulated production of tumor necrosis factor-alpha, interleuk in-1 beta, interleukin-6, and interferon-gamma; on the in vivo plasma levels of tumor necrosis factor-alpha and interleukin-6; and on plasma concentrations of cortisol and growth hormone. Ten healthy men (18-35 yr) participated in two experimental sessions in a balanced order. On one occasion, subjects fasted; on the other, they received a high-pro tein meal at 1230. Blood was sampled every 15 min. Whereas the numbers of neutrophils and platelets were increased for more than 2.5 h after meal intake (P < 0.01), lymphocyte counts decreased (P < 0.01). Meal intake also decreased the production of interferon-gamma but did not a ffect the production and plasma levels of the other cytokines. Changes in immune cell. distribution and function were accompanied by a stron g postprandial rise in plasma cortisol concentrations. Some of the sys temic immune changes, Like the emigration of lymphocytes, probably int o extravascular abdominal tissues, may serve to support local immune d efense.