[Effect of arginine on lymphocyte responses to ConA in burned mice]

It is well accepted that nutritional support improves the immunologic functions in burned patients. Arginine has been demonstrated to have tissue-specific properties which induce beneficial effects upon the immune system. A series of experiments are carried out, in order to evaluate the immune effect of arginine on burned mice. 1. Lymphocytes from both burned and unburned mice are harvested and incubated in various concentrations of arginine solution for 72 hours, and ConA-stimulating lymphocyte transformation is determined after incubation. 2. Burned animals are divided into four groups. Standard diets for nutritional support are formulated. These formulas contain an identical carbohydrate and lipid (61% and 15% of total energy respectively) intake with varied proportions of protein for each group (24%, 23%, 22%, and 20% of total energy, respectively), in addition. 0%, 1%, 2% and 4% of protein energy is supplied by arginine for different groups. Lymphocyte proliferations in responses to ConA stimulation are determined on the 7th postburn day. The data shows that, in vitro study, increasing arginine concentrations enhanced lymphocyte responses to ConA. The arginine needed level for optimal lymphocyte responses is 1.8 mmol/L in burned mice and 0.9 mmol/L in unburned controls. This difference indicates that in burned mice, a higher arginine concentration is required for better lymphocyte responses. On the contrary, further increase of arginine concentration do not give better response. When varied amounts of arginine are given in the diet to the burned mice, the degree of lymphocyte response to ConA is different. The amount of arginine which supplies 2% of total energy is found to be optimal.