Mitogenic activity and the induction of tumor necrosis factor by lipopeptide analogs of the N-terminal part of lipoprotein in the outer membrane of Escherichia coli.

Mitogenicity and the production of tumor necrosis factor (TNF) by a chemically synthesized lipotetrapeptide analog (KAB-8), S-[2,3-bis(palmitoyloxy)-2R-propyl]-N-[(2,2,2)-trichloro- ethoxycarbonyl: Troc group]-(R)-cysteinyl-(S)-seryl-(S)-seryl-(S)-asparagine, the amino acid sequence of which corresponds to that of the lipopeptide part of lipoprotein in Escherichia coli, and several derivatives (KAB-30-41), which possessed the altered glycerocysteine moiety, were examined. A 1-cysteinyl glycerol skeleton-type compound (KAB-8), a propane-type compound (KAB-31), a homoglycerol-type (KAB-39 and 40) and a 2-cysteinyl glycerol-type (KAB-41) exhibited mitogenic activity on splenocytes from C3H/He mice at various concentrations ranging from 0.4 to 100 micrograms/ml. However, propane-type compounds, except KAB-31, and ethane-type compounds showed lower mitogenic activity than other types of compounds. Compounds KAB-8, 31, 40 and 41 induced the production of TNF in peritoneal exudated macrophages from C3H/He mice at concentrations of 25 and 50 micrograms/ml. The results indicate that the structural differences of the glycerol moiety in the synthetic lipopeptides affect the potency of its biological activities.