Alteration of antibody-mediated responses of suckling mice to T-cell-dependent and independent antigens by maternal marginal zinc deficiency: restoration of responsivity by nutritional repletion.

To further characterize the effects of marginal zinc deficiency on the development of the immune system of the suckling A/J mouse, dams were fed marginal (1.6 micrograms Zn/g), intake restricted (30 micrograms Zn/g) or adequate (30 micrograms Zn/g) levels of dietary zinc days 5-17 postpartum. Marginal levels of zinc had little effect on the body weight of dams; however, their pups were only 71-75% the weight of control pups. In response to two T-cell independent (TI) antigens pups of low zinc dams could produce only 49 and 44% as many antibody-producing cells per spleen as control pups. Pups of restricted-fed dams produced about 60% as many cells as controls for each TI antigen. The avidities of the plaques produced by pups of restricted and control dams in response to TI antigens were nearly the same but were 5.5 times higher than the relative avidities of the antibodies produced by pups of low zinc dams. The responses of the deficient pups to sheep red blood cells (SRBC), a T-dependent (TD) antigen, were 25-30% of response of control and 56-75% of that of restricted pups depending on whether direct (IgM) or indirect (IgG) plaques were enumerated. The data demonstrate that marginal deficiencies in zinc during lactation greatly reduce the ability of suckling pups to mount antibody-mediated responses and suggest that the kinds of lymphocyte subsets found in deficient pups are altered. However, antibody-mediated response capacity was normal in the deficient pups following a short period of zinc supplementation.