Delayed hypersensitivity and lesions following isoimmunization with modified rat male accessory glands: kinetics of...

The kinetics of the cellular immune response to rat male accessory glands were studied in Wistar rats isoimmunized with modified rat male accessory glands extract and complete Freund's adjuvant at 0, 30 and 45 days. The animals were divided into seven groups, and each group was sacrificed weekly. One immunization was sufficient for the induction of 2-, 6- and 24-h footpad reactivity. The reaction increased until 21 days post-immunization. After the second injection the reaction decreased and was negative 12 days later. Migration inhibitory factor (MIF) activity monitored by a mixed-direct assay was demonstrated in rats from all groups except in the animals studied at day 42 in which macrophage migration was markedly stimulated. The absence of MIF activity correlated with a lack of delayed type hypersensitivity (DTH) response. The humoral response was studied and detected by passive hemagglutination in a few sera after the first immunization. A second injection was necessary to obtain a more frequent occurrence and higher titres of antibodies. Histological modifications in the target organs started to appear in the group of animals studied at 35 days and were characterized by a mononuclear infiltrate in the prostate, coagulating glands and seminal vesicles. In several cases there was also infiltration of polymorphonuclear cells. Specimens obtained at 35 days showed the most severe lesions.