Mycoplasmal Lipopeptide MALP-2 Induces the Chemoattractant Proteins Macrophage Inflammatory Protein 1α (MIP-1α), Monocyte Chemoattractant Protein 1, and MIP-2 and Promotes Leukocyte Infiltration in Mice

Abstract

Natural as well as experimental infections with pathogenic mycoplasmas lead to cellular responses characterized by early polymorphonuclear leukocyte influx, which in turn is followed by infiltration of macrophages. Since some of the most potent leukocyte chemoattractants are macrophage products, we investigated whether the 2-kDa macrophage-activating lipopeptide (MALP-2) from Mycoplasma fermentans was capable of inducing chemoattractant chemokines and initiating an in vivo inflammatory effect. MALP-2 was a potent in vitro inducer of the chemokines macrophage inflammatory protein 1α (MIP-1α), monocyte chemoattractant protein 1 (MCP-1), and MIP-2, yielding a maximal response at 0.1 ng/ml (5 × 10−11 M). Leukocyte infiltration was determined after intraperitoneal injection of MALP-2, liposome-encapsulated MALP-2, and heat-killed mycoplasmas. There was a steady increase in the number of peritoneal cells over 72 h in response to these agents. Polymorph counts were maximal by 24 to 48 h, decreasing thereafter. Monocytes/macrophages had significantly increased after 3 days. MIP-1α, MCP-1, and MIP-2 levels in serum or peritoneal lavage fluid were determined. MIP-1α and MCP-1 levels were elevated by 2 to 6 h after injection and were still above control values after 24 h. In contrast, MIP-2 levels reached their maximum at 2 h, dropping to control values after 24 h. We conclude that macrophage-stimulating mycoplasmal lipoproteins, exemplified by MALP-2, play an important role in the late phase of phagocyte recruitment at sites of infection and that this is affected by leukoattractive chemokines.

Differential recognition of structural details of bacterial lipopeptides by toll-like receptors

“…7, oxidation to the sulfoxide resulted in lowering the specific activity by four orders of magnitude when compared to MALP-2. We next studied the stability of MALP-2 in cell homogenates of peritoneal cells which were enriched with neutrophils by intraperitoneal injection of MALP-2 24 h prior to cell harvesting [25] thus mimicking the scenario at an inflammatory site rich in activated M ¶ and PMN. Cells were harvested, divided into two equal portions and sonicated.…”

Efficient mucosal delivery of the HIV‐1 Tat protein using the synthetic lipopeptide MALP‐2 as adjuvant

“…vaccination with biologically active Tat protein and MALP-2 was also able to induce IFN-+ -producing cells, which constitute a correlate for protection. For this reason, splenocytes from vaccinated animals were incubated for 16 h in the absence or presence of a pool of Tat peptides that were known to be targets for CTL in the murine system (ACTNCYCKKCCFHCQVCFIT [aa [21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40], WKHPGSQ- [35] and unpublished data), and the number of IFN-+ -secreting cells was determined by ELISPOT. The results demonstrated that the frequency of IFN-+secreting cells was significantly higher in mice vaccinated with Tat protein + MALP-2 than in the other groups (Fig.…”

“…We have recently found that a synthetic derivative (S-[2,3-bispalmitoyloxypropyl] cysteinyl-GNNDESNISF-KEK) of the Mycoplasma-derived macrophage-activating lipopeptide-2 (MALP-2) is a potent adjuvant when coadministered with antigens by the mucosal route [27]. MALP-2 is a powerful inducer of chemokines and cytokines as a result of signaling via Toll-like receptors 2 and 6 [28][29][30], which enhances humoral and cellular antigenspecific immune responses. In the present study we have investigated whether the HIV-1 Tat protein can be efficiently delivered by the intranasal (i.n.)…”

Fibrin as a delivery vehicle for active macrophage activator lipoprotein‐2 peptide: in vitro studies

“…[20][21][22] MALP-2 was tested successfully in animal studies and has been shown to enhance wound healing. 23,24 Thus, the delivery vehicle is as important as the substance itself. Fibrin has been used for delivery of growth factors and cells for many years.…”