The role of hypothalamic centres in the immune specific response

Four groups of rats were bilaterally lesioned in the anterior, lateral, tuberal and mammillary areas of hypothalamus. Seven days later these rats, as well as controls, were immunized concomitantly with three antigens: Salmonella enteritidis, sheep red blood cells and Myxovirus influenzae A (H3N2). The primary and the secondary response were tested. The bacterial and erythrocytic antigens, with marked immunogenetic capacity, produced immune responses, which were not significantly influenced by hypothalamic lesions. The immune primary and secondary response to influenza A virus is wholly suppressed in animals with lesions in tuberal and mammillary areas of the hypothalamus. It is reduced in animals with lesions in lateral and anterior regions, as compared with controls. The secondary response is greater and more rapid in controls. It is reduced in animals with lesions in anterior and lateral hypothalamus and suppressed in those with lesions at tuberal and mammillary level. It therefore seems that the modulatory intervention of the hypothalamus in the immune process depends on the antigen, on the antigen, on the intensity of its direct effects on the immuno-competent and accessory cells and on the condition of the hypothalamic centers.