HISTOPATHOLOGICAL STUDIES ON THE LOCAL REACTIONS INDUCED BY COMPLETE FREUND ADJUVANT (CFA), BACTERIAL LIPOPOLYSACCHARIDE (LPS), AND SYNTHETIC LIPOPEPTIDE-(P3C) CONJUGATES

The inflammatory reactions following subcutaneous application of adjuvants revealed characteristic pathological patterns. The injection of complete Freund's adjuvant (CFA) resulted in the formation of large lipid deposits encircled by an inflammatory reaction and concentrically arranged collagen bundles. Bacterial lipopolysaccharide (LPS) caused granulomatous aggregations of mononuclear cells with thrombotic vessel occlusions. Inoculation of the lipopeptide adjuvants induced accumulation of mononuclear cells with only minimal fibrotic changes which were resolved after day 28. Lipopeptide conjugates based on the head group tripalmitoyl-S-glyceryl-cysteinyl-serine (P3CS) can thus be used as effective immunogens and adjuvants without long-term tissue damage.