Effect of serum source on protein-free diet lymphocyte blastogenesis

The influence of protein depletion on serum factors in PHA lymphocyte blastogenesis was studied in a rat model. Buffalo rats were divided randomly into two groups and fed either a protein-free (PF) diet or a regular 25% protein diet (RD). At weekly intervals, lymph node lymphocytes were cultured with PHA in either autologous or pooled 10% rat serum. For weeks 2 through 6, PHA stimulated blastogenesis of lymphocytes from rats maintained on PF diet incubated with autologous serum decreased significantly compared with RD lymphocytes cultured with RD serum. At week 4, PHA blastogenesis of PF lymphocytes cultured with RD serum was similar to that of RD lymphocytes incubated with RD serum. AT weeks 5 and 6, PHA stimulation of PF lymphocytes assayed with RD serum was depressed compared with RD lymphocytes cultured with RD. For weeks 4 through 6, blastogenesis of RD lymphocytes assayed with PF serum decreased significantly compared with RD lymphocytes incubated with RD serum. Three weeks of protein repletion of rats previously on a PF diet for 6 weeks restored PHA blastogenesis to that observed for lymphocytes from animals in the RD group. The data suggested that suppression of PHA blastogenesis of lymphocytes from rats maintained on PF diet involved a serum factor in the early stages of protein depletion and an additional defect (not serum related) in lymphocyte blastogenesis after prolonged protein depletion. In addition, this defect was corrected after a period repletion.