Immunosuppressive activity of a polychlorinated biphenyl preparation on the humoral immune response in guinea pigs

Abstract

Three groups of 12 female albino guinea pigs were fed 0, 10 and 50 ppm Aroclor 1260 (PCB) for 8 wk. In half of the animals a function test of the immunological system was carried out: tetanus toxoid injection was used to study the humoral response. At the end of the experiment cellulose acetate electrophoresis was used to determine the serum proteins, including the γ-globulin level. The number of γ-globulin-containing cells in popliteal lymph nodes was determined semiquantitatively with the direct fluorescent antibody technique. Both these techniques seemed to be sensitive parameters for the immunosuppressive action of PCB in the tetanus toxoid-stimulated animals.

In the unstimulated guinea pigs no suppressive activity could be found. Other parameters, such as leukocyte counts, weights of thymus, spleen and lymph nodes and number of follicles and pyroninophilic cells, were in general not sensitive enough to detect an effect of PCB feeding. Absence of effects on weight and histomorphology of thymus and adrenal gland indicated that not stress but PCB itself was responsible for the immunosuppressive activity.