Undernutrition without malnutrition restricts the numbers and proportions of Ly-1 B lymphocytes in autoimmune (MRL/I and BXSB) mice.

MRL/Mp-lpr/lpr (MRL/l) and BXSB mice represent inbred mouse strains in which lymphoproliferative disease and autoimmune disease that includes lethal renal disease routinely occurs by 6 months of age. Chronic energy intake restriction increases longevity and health span of MRL/l and BXSB mice as it does in mice of other short-lived as well as long-lived strains. Chronic energy intake restriction forestalls development of the lymphoproliferative process, prevents development of renal lesions, decreases levels of circulating immune complexes, and permits maintenance of vigorous immunologic function with age. We have reported that in autoimmune-prone mice, a population of Ly-1 B lymphocytes that is associated with autoimmune disease and is greatly expanded among cells of the spleen, peritoneal exudate, and peripheral blood can be reduced in proportion as a consequence of undernutrition without malnutrition. Herein, we demonstrate that in MRL/l and BXSB mice, chronic energy intake restriction imposed at weaning inhibited accumulation of Ly-1 B lymphocytes throughout the lymphoid system, i.e., among cells of the spleen, thymus, mesenteric lymph nodes, bone marrow, peritoneal exudate, and peripheral blood when these tissues or fluids were studied at age 3 or 5 months. These results extend our previous finding that autoimmune-prone mice possess unusually large numbers of Ly-1 B cells in their lymphoid tissues which can be reduced in frequency as a function of diet toward the levels present in long-lived autoimmune-resistant mice.