FLOW CYTOMETRIC ANALYSIS OF THE PHENOTYPIC DISTRIBUTION OF SPLENIC LYMPHOCYTES IN ZINC-DEFICIENT ADULT MICE

Many immunodeficiency states create an imbalance in the ratio of T cells to B cells or in the subsets of lymphocytes found within these two major classes. A 30-d period of suboptimal intake of zinc often caused a 50% decrease in the total number of splenic lymphocytes in young adult mice. One- and two-color flow cytometric analysis was made of the residual splenocytes of the zinc-deficient mice to determine whether the deficiency had also altered the composition or phenotypic distribution of any of the major subsets of T cells or B cells. Marginally zinc-deficient mice had a normal ratio of T cells to B cells with no notable change in the subsets of lymphocytes making up these two classes. Severely zinc-deficient mice that exhibited a significant degree of parakeratosis demonstrated a 20% increase in the overall ratio of T helper to T suppressor/cytotoxic cells as well as a modest decline in the percentage of B cells (5-8%). The latter decrease was not in the B cells bearing immunoglobulin M or D but in the minor subsets bearing other immunoglobulin isotypes. Thus it seems that, whereas zinc deficiency caused significant reductions in the total numbers of splenic lymphocytes, it caused no significant change in the composition of the splenic lymphocytes except in the most severe cases.