To evaluate the functional significance of
triphenyltin hydroxide (TPTH)-induced
lymphopenia and lymphocyte depletion in thymus-dependent areas of spleen and lymph nodes, various immune function studies were carried out after 3 or 4 weeks TPTH exposure. Weaned male rats were fed a diet containing 25 mg TPTH/kg, a concentration that did not influence food intake and
weight gain.
TBTO exposure was continued during the course of the function tests. As parameters of the cell-mediated immunity in 2 experiments the delayed-type
hypersensitivity reactions to
ovalbumin and
tuberculin were significantly suppressed. No effect was observed on allograft rejection, splenic clearance of Listeria monocytogenes at days 5 and 6 after
infection, and responsiveness of thymocytes to different T-cell
mitogens. In contrast, the response of splenic lymphocytes to the T-cell
mitogen phytohaemagglutinin was significantly suppressed. As TPTH treatment reduced the number of spleen cells, mitogenic response calculated per whole spleen was significantly depressed. Regarding the humoral immunity, no effect was observed on serum
IgM and
IgG levels, on the thymus-independent
IgM response to E. coli
lipopolysaccharide (LPS), and on the primary and secondary
IgM and
IgG response to the thymus-dependent
antigen tetanus toxoid. Also, no effect was found on phagocytic and killing capacity of macrophages as demonstrated by unaltered splenic clearance of L. monocytogenes at days 1 and 2 after
infection. Slightly enhanced mortality of TPTH-treated animals was observed in a L. monocytogenes mortality assay. Finally, TPTH did not increase the susceptibility of rats to
endotoxin (LPS).