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.