Acetylated diamines inhibit endotoxin-induced lymphocyte activation.

Fully acetylated diamines hexamethylenebisacetamide (HMBA) and diacetylputrescine (tetramethylenebisacetamide, TMBA) cause inhibition of murine B lymphocyte activation in the absence of ruminant serum. Mitogenesis induced by LPS, LAP, and 8-BrcGMP was profoundly inhibited in the presence of 3 mM HMBA and TMBA. PHA-stimulated thymidine uptake was not affected. Higher levels of the acetylated polyamines were toxic to lymphocytes. Immunoglobulin secretion by LPS-stimulated spleen cells was inhibited in similar fashion. This inhibition requires the early addition of the polyamines and does not appear to be associated with direct inhibition of DNA synthesis. These data support the hypothesis that polyamines represent immunomodulatory agents and suggest that acetylated derivatives of polyamines may also have activity in regulating B lymphocyte activation.