Effect of Protein Deficiency on the Spleen and Antibody Formation in Rats

As protein malnutrition frequently has been associated with lowered resistance and poor immune response, a study was undertaken to determine which aspects of the primary immune response may be impaired in protein deficiency and to describe such effects in terms of tissue components related to synthesis of plasma proteins. Protein-deficient and normal adult male rats were immunized with sheep erythrocytes and killed 6 days later. Spleens of protein-deficient rats were smaller and contained fewer cells, less nitrogen, less RNA, and more DNA per cell than those of controls. These changes were compared with those observed in liver as a result of protein depletion. In depleted animals, numbers of specific antibody-forming cells (AFC) and amounts of circulating antibody were about one-third of normal, while the amount of γ-globulin was two-thirds of normal. Since antibody production per AFC did not decrease in deficient animals, the depression of antibody titers in protein deficiency could be attributed largely to the reduction in numbers of AFC’s in the spleen.