Immunosuppressive activity of a purified spleen extract (lymphocytic chalone?) is not due to polyamines spermine and spermidine.

Spermine, spermidine and a purified spleen extract (PSE) have been compared in vivo in these three tests: hemolytic plaque forming capacity in sensitized mice, delayed hypersensitivity reaction and 3H-thymidine incorporation into various tissue cells. The results obtained demonstrated that the immunosuppressive activity of PSE cannot be attributed to those polyamines. Ion exchange analysis of PSE before and after acid hydrolysis confirmed the absence of free and/or bound polyamines in the studied extract.