The effect of a fever-like response on the secondary antibody response of the rat

Since fever appears to modulate the primary humoral immune response, a fever-like response was induced in 18 rats by cooling their preoptic areas during the first five days after re-immunization with sheep erythrocytes. The titre of antibodies in these rats was the same as that in 17 control animals, indicating that the febrile response does not influence the magnitude of the secondary antibody response. It is suggested that only those fevers evolving in the early phase of a primary, natural infection may modulate the magnitude of the humoral immune response to the pathogen.