LIPID MEDIATORS OF IMMUNE-REACTIONS - EFFECT OF A LINKED PHOSPHORYLSERINE GROUP

Immunoregulation by lipids containing the phosphorylserine (PHS) group has been studied in rodent peritoneal mast cells and human peripheral blood lymphocytes. When PHS is linked to a phospholipid backbone (mon o- and diacylglycerol), mast cell activation is produced. However, the effect decreases linking the PHS group to long chain alkanols and is abolished in cholesteryl-PHS, showing that the acylglycerol moiety par ticipates in mast cell activation. Phospholipids containing the PHS gr oup inhibit proliferation of activated peripheral blood lymphocytes. I n contrast to mast cells, this effect is retained in alkyl-PHS and is enhanced in cholesteryl-PHS, indicating that in this case the PHS grou p is the main effector. Among non-phospholipid PHSs, cholesteryl-PHS h as been the most interesting since it associates lack of mast cell act ivation and high inhibitory activity on peripheral blood lymphocytes. This selectivity suggests that this compound may have a potential as a n immunosuppressive agent.