The effect of triiodothyronine on the primary antibody response to sheep red blood cells in moderately undernourished weanling mice

Abstract

Weanling male CBA/J mice were fed a complete, semipurified diet either ad libitum or in restricted daily quantities. The undernourished mice were fed such that they gained 18% of their initial weight over the 6-week experimental period. A 2×2 design was used in which animals from each dietary group received food either with or without a triiodothyronine (T 3) supplement of 0.2 mg/kg diet. In mice immunized with sheep red blood cells, undernutrition decreased the number of nucleated spleen cells and the number of IgG plaque-forming cells (PFC's) per spleen, increased the number of IgM PFC's per 10 6 nucleated spleen cells, and had no effect on the number of IgM PFC's per spleen, the number of IgG PFC's per 10 6 nucleated spleen cells or the serum hemagglutinin titre. T 3 supplements increased nucleated spleen cell numbers and IgM PFC's per spleen in both well-nourished and undernourished mice, and also increased hemagglutinin titres in undernourished mice. According to carcass composition (dry matter, protein and lipid) and serum protein measurements the effect of T 3 was not attributable to improved nutritional status in spite of increased feed intake by the T 3-treated animals.