thymosin and Protein-Energy-Malnutrition

The present studies were performed to determine the effects of severe protein deficiency and subsequent injection of thymosin fraction 5 (TF5) on T and B cell functions. BALB/c mice, 4 weeks old, were fed a normal protein (21%), a low protein (4%) or a protein free (0%) diet and then injected with TF5 or buffer (PBS). A significant increase was observed in the PHA (phytohemagglutinin) and LPS (lipopolysaccharide) induced mitogenesis with increasing age of the well-nourished, PBS injected animals. The severely protein malnourished mice, PBS injected and the well nourished mice, injected with TF5 had smaller increases in both B and T cell mitogenesis with increasing age. TF5 injection of the malnourished mice increased PHA and LPS mitogenesis nearly to the levels of the well-nourished mice. The protein malnourished mice consistently had higher serum corticosteroid levels than controls. No changes in serum corticosteroids were observed with TF5 injection of controls, but there was a significant decrease in the corticosteroid levels of the severely malnourished with TF5 injection. Cytoxicity assays of T cell function, antibody dependent cellular cytoxicity and cytoxicity to mouse thymona tumor cells, in mice fed moderately protein deficient diets showed suppression compared to controls fed 20% protein. TF5 injection partially and temporarily increased these functions in the malnourished mice.

Topics: Animals; Antibody-Dependent Cell Cytotoxicity; Body Weight; Female; Immunosuppression Therapy; Lymphocyte Activation; Male; Mice; Mice, Inbred BALB C; Organ Size; Protein-Energy Malnutrition; T-Lymphocytes; Thymosin

Moderate protein malnutrition retarded the i.p. proliferation of L1210 mouse leukemia cells in BALB/c mice. The increased resistance against leukemia cell growth in protein-malnourished mice was correlated with increased in vitro mitogenic responsiveness of spleen lymphocytes to phytohemagglutinin and increased levels of serum corticosterone but could not be correlated with altered development of splenic lymphocyte-mediated cytotoxicity. The increased resistance against leukemia cells in well-fed mice treated with thymosin alone could not be correlated with an increase in any of these parameters. Treatment with Thymosin Fraction V further increased the resistance of protein-malnourished mice to i.p. leukemia cell growth. The increased resistance of these mice to tumor cell growth was correlated with increased splenic lymphocyte mitogenic responsiveness to phytohemagglutinin, elevated serum corticosterone levels, and a slight increase in lymphocyte-mediated cytotoxicity 14 days after tumor challenge. For 7 days after the last treatment, protein-malnourished mice had reduced serum corticosterone levels. Nevertheless, the serum corticosterone levels were still higher than normal in these mice.

Topics: Animals; Corticosterone; Cytotoxicity, Immunologic; Female; Leukemia L1210; Lymphocytes; Mice; Mice, Inbred BALB C; Protein-Energy Malnutrition; Thymosin; Thymus Hormones