Macrophage activation by bacterial cell walls and related synthetic compounds

Abstract

Activation of peritoneal macrophages from guinea pigs by various bacterial cell walls, M-1 endo-N-acetylmuramidase enzymatically digested bacterial cell walls and synthetic muramyl dipeptides was studied in terms of stimulation of ["4C] glucosamine incorporation. All test bacterial cell wall preparations significantly increased a [14C]glucosamine uptake by the macrophages. Some of the watersoluble M-1 enzyme digests also exerted stimulating effects on macrophages, although the activity of the digests was found to be weaker than those of original cell walls. Furthermore, an adjuvant-active synthetic MurNAc-L-Ala-D-isoGln (MDP) showed a weak but significant activity, whereas an adjuvant-inactive analog, MurNAc-L-Ala-L-isoGln, did not show a significant activity, at least with the dose of 100 ljg. Additional studies with 6-0-acyl derivatives of MDP revealed that 6-0-(2-tetradecylhexadecanoyl)-MDP and 6-0-(3-hydroxy-2-tetradecyloctadecanoyl)-MDP exhibit stronger macrophage-stimulating effects than MDP. It can be concluded from the above findings that MDP is the essential structure responsible for stimulating the activity of cell walls on guinea pig peritoneal macrophages, but it requires a particle state, which results from an additive character of lipophilicity, to exert the activity fully and effectively.Stimulation of radiolabeled glucosamine incorporation by macrophages as one expression of macrophage activation was first shown by Hammond and Dvorak (8, 9) on the reaction of peritoneal macrophages from antigen-primed guinea pigs with a specific antigen in vitro. This study preceded the finding that plant lectins, concanavalin A, and phytohemagglutinin stimulated macrophages from nonimmunized animals to increase glucosamine uptake (9) and that BCG cell walls had a similar activity (11).In this study, we investigated the stimulating effects of bacterial cell walls and related compounds, either enzymatically obtained or synthetic, upon peritoneal macrophages from guinea pigs in terms of elevation of glucosamine uptake. The study was undertaken to determine the chemical structure and physical state required for the macrophage activation as determined by the increase of glucosamine incorporation. MATERIALS AND METHODSCell wall preparations. Cells as a starting material for isolation of the walls were cultured under the 48 following conditions. Mycobacterium smegmatis ATCC 19420 was grown as a pellicle on 250 ml of Sauton medium in Roux flasks at 30'C for 14 days, Nocardia corynebacteriodes ATCC 14898 was grown in a medium (pH 7.2) containing 1% maltose, 1% meat extract, 1% polypeptone, 0.5% NaCl, and the deforming agents (0.2% silicone KM-70 and 0.01% Karaline 102). Streptomyces gardneri ATCC 23911 was grown with aeration in a medium (pH 7.2) consisting of 1% glucose, 0.5% polypeptone, 0.3% malt extract, and the above deforming agents. Cultivations of N. corynebacteriodes and S. gardneri were made in 20-liter Jar fermentors containing 10-liter portions of the above media by incubating each 100 ml of a seed culture ...

Species dependency of macrophage activation by bacterial peptidoglycans

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The effect of various bacterial cell wall components on in vitro biologicalMuramyl dipeptide (N-acetylmuramyl-L-alanyl-D-isoglutamine, MDP) is the minimal structure of bacterial cell wall peptidoglycan required for various biological activities (2,29,46). Numerous glycopeptides with various immunomodulating address:

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The pathogenesis of group a streptococcal cell wall‐induced polyarthritis in the rat comparative studies in arthritis resistant and susceptible inbred rat strains

“…For example, they may initiate acute inflammation by direct activation of the alternative pathway of the complement system (1). They may also directly activate macrophages (immunoadjuvant activity) and indirectly modulate the activity of T and B lymphocytes, fibroblasts, and other cells involved in acute and chronic inflammation (2)(3)(4)(5)(6)(7). Moreover, these polyclonal activators may also preferentially induce autoantibodies such as rheumatoid factor (8-9).…”

Effect of Muramyldipeptide, a Synthetic Bacterial Adjuvant, on Enzyme Release from Cultured Mouse Macrophages

“…It is now well established that MDP activates peritoneal macrophages as measured by several parameters (14,23,25,31,33,37, unpublished data), including antibacterial capacity (unpublished data) as originally defined by Mackaness (19). Moreover, accumulating lines of evidence favor direct activation of macrophages without involvement of T-lymphocytes or their mediators (14,23,25,33,37,39).…”

“…With the aid of chemical synthesis of this compound and its analogs, a very high stereospecificity for adjuvant activity has been found in several systems (I, 3, 16, 17). In parallel with these findings, a variety of biological activities of MDP have been observed and shown to depend on the same specific structure (6,31,34). In vivo, MDP has been reported to possess pyrogenicity (16), stimulatory effect on the reticuloendothelial system (35), granulomatogenicity in several animals (10,32) and arthritogenicity in the rat (22).…”