Synthesis and modulation of cytokine production by two new adamantane substituted acyclic desmuramyldipeptide analogs.

Two new adamantyl-desmuramyldipeptides LK 415 and LK 517 with 1-adamantylcarboxamido moiety as a replacement for muramyldipeptide's N-acetylglucosamine fragment were synthesized. Their efficacy to modulate the production of cytokines was measured in vitro in ionomycin and phorbol-12-myristate-13-acetate (PMA) activated cultures of human peripheral blood mononuclear cells (PBMC), co-incubated with the substances tested. The results were compared with the activity of muramyldipeptide (MDP). All three substances are strong up-regulators of IL-12 synthesis and hence of the IFN gamma synthesis as well. While MDP and LK 415 are relatively ineffective in modulation of IL-2, IL-4 and IL-10 production in vitro, the synthesis of all three cytokines is considerably up-regulated when peripheral blood mononuclear cells are co-incubated with LK 517. It seems likely that the introduction of the diethyl phosphonate moiety into LK 517 is of great importance for the augmented T-cell cytokine production.