IL-6 mediates 11βHSD type 2 to effect progression of the mycobacterial cord factor trehalose 6,6'-dimycolate-induced granulomatous response

Granulomatous structures are highly dynamic during active mycobacterial infection, with accompanying responsive inflammation contributing to modulation of pathology throughout the course of disease. The heightened inflammatory response coinciding with initiation and maintenance of newly developing granulomatous structures must be limited to avoid excessive damage to bystander tissue. Modulating the cellular bioavailability of glucocorticoids by local regulation of 11βHSD enzymes within responding tissue and parenchyma would allow controlled inflammatory response during infection. Mycobacterial glycolipid trehalose 6,6'-dimycolate was used to induce strong pulmonary granulomatous inflammation immunopathology. Pulmonary corticosterone was significantly increased at days 3 and 5 after administration. An inverse relationship of 11βHSD1 and 11βHSD2 message correlated with pathology development. Immunohistochemical analysis also demonstrated that 11βHSD2 is expressed in proximity to granulomatous lesions. A role for pro-inflammatory IL-6 cytokine in regulation of converting enzymes to control the granulomatous response was confirmed using gene-disrupted IL-6-/- mice. A model is proposed linking IL-6 to endocrine-derived factors which allows modification of active corticosterone into inert 11-dehydrocorticosterone at the site of granuloma formation to limit excessive parenchymal damage.

Molecular and supra-molecular structure related differences in toxicity and granulomatogenic activity of mycobacterial cord factor in mice

To establish the structure biological activity relationship of cord factor (trehalose 6,6'-dimycolate, TDM), we compared the molecular or supra-molecular structure of TDM micelles with toxicity, thymic atrophy and granulomatogenicity in lungs and spleen of BALB/c mice. According to the difference in the mycolyl subclass composition, TDM was divided into two groups, one possessing alpha-, methoxy- and keto-mycolates in M. tuberculosis H37Rv, M. bovis BCG and M. kansasii (group A) and the other having alpha-, keto- and wax ester-mycolates in M. avium serotype 4, M. phlei and M. flavescens (group B), although mycolic acid molecular species composition differed in each group considerably. Supra-molecular structure of TDM micelle differed species to species substantially and the micelle size of TDM from M. bovis BCG Connaught was the largest. The highest toxicity was shown with TDM from M. tuberculosis H37Rv which possessed the highest amount of alpha- (47.3%) and methoxy-mycolates (40.8%), while TDM from M. phlei having the low amount of alpha-mycolate (11.6%) showed almost no toxicity with the given doses. The thymic atrophy was observed with TDM from group A, but not with TDM from group B. On the other hand, TDM from group B showed massive lung granulomatogenic activity based on the histological observations and organ indices. Taken together, group A TDM showed a wide variety of micelle sizes and specific surface areas, high to low toxicity and marked to moderate granulomatogenicity, while group B TDM showed smaller sizes of micelles and larger specific surface areas, lower toxicity but higher granulomatogenicity in lungs. Existence of higher amount of longer chain alpha-mycolates in TDM appeared to be essential for high toxicity and thymic apoptotic activity, whereas TDM possessing wax ester-mycolate with smaller sized micelles seemed to be less toxic, but more granulomatogenic in lungs in mice. Thus, the mycolic acid subclass and molecular species composition of TDM affect critically the micelle forms, toxicity and granulomatogenicity in mice, while the relative abundances and carbon chain length of alpha-mycolate affected the toxicity in mice.

Mycobacterial sulfolipid shows a virulence by inhibiting cord factor induced granuloma formation and TNF-alpha release

Virulence mechanism of infection with Mycobacterium tuberculosis is currently focused to be clarified in the context of cell surface lipid molecule. Comparing two mycobacterial glycolipids, we observed toxicity and prominent granulomatogenic activity of trehalose 6,6'-dimycolate (TDM) injection in mice, evident by delayed body weight gain and histological observations, whereas 2,3,6,6'-tetraacyl trehalose 2'-sulfate (SL) was non-toxic and non-granulomatogenic. Likewise, TDM but not SL caused temporarily, but marked increase of lung indices, indicative of massive granuloma formation. Interestingly, co-administration of TDM and SL prevented these symptoms distinctively and SL inhibited TDM-induced release of tumor necrosis factor alpha (TNF-alpha) in a dose-dependent manner. Histological findings and organ index changes also showed marked inhibition of TDM induced granuloma formation by co-administration of SL. Simultaneous injection of SL together with TDM was highly effective for this protection, as neither injection 1h before nor after TDM injection showed highly inhibitory. In parallel studies on a cellular level, TDM elicited strong TNF-alpha release from alveolar but not from peritoneal macrophages in vitro. This effect was blocked when alveolar macrophages were incubated in wells simultaneously coated with TDM and SL, indicating that SL suppresses TDM-induced TNF-alpha release from macrophages. Our results suggest a novel mechanism by which SL could contribute to virulence at early stage of mycobacterial infection or stimulation with the glycolipids by counteracting the immunopotentiating effect of TDM.

Trehalose 6,6'-dimycolate and lipid in the pathogenesis of caseating granulomas of tuberculosis in mice

Trehalose 6,6'-dimycolate (TDM) is the most abundant, most granulomagenic, and most toxic lipid extractable from the surface of virulent Mycobacterium tuberculosis (MTB). We further examined its toxicity, which requires activation by oily surfaces. Injections of MTB and/or TDM into sensitized mice induced caseating granulomas that centered on oil droplets. If large doses of MTB were injected in saline, caseating granulomas developed in adipose tissue, but MTB with surface TDM removed induced only acute inflammation that did not persist. Variations in protocols produced several variants of caseating granulomas, each with characteristics of human tuberculosis. In each instance, MTB were localized in fat cells or oil drops during initiation of caseating granulomas suggesting that necrosis was caused by activation of the toxicity of TDM toxicity. Evidence extending these findings to the lung was derived from the observation that in sensitized mice, as in humans, tuberculosis development stimulates accumulation of lipid selectively in alveoli. MTB preferentially associated with lipid droplets in developing necrotic foci in late-stage murine tuberculosis. This supports the hypothesis that pulmonary tuberculosis sequesters MTB in a protected environment that accumulates lipid until it is able to activate the toxicity of TDM and initiate necrosis that results in caseating granulomas.

In vivo activity of released cell wall lipids of Mycobacterium bovis bacillus Calmette-Guérin is due principally to trehalose mycolates

The hallmark of Mycobacterium-induced pathology is granulomatous inflammation at the site of infection. Mycobacterial lipids are potent immunomodulators that contribute to the granulomatous response and are released in appreciable quantities by intracellular bacilli. Previously we investigated the granulomagenic nature of the peripheral cell wall lipids of Mycobacterium bovis bacillus Calmette-Guérin (BCG) by coating the lipids onto 90-microm diameter microspheres that were mixed into Matrigel matrix with syngeneic bone marrow-derived macrophages and injected i.p. into mice. These studies demonstrated that BCG lipids elicit proinflammatory cytokines and recruit leukocytes. In the current study we determined the lipids responsible for this proinflammatory effect. BCG-derived cell wall lipids were fractionated and purified by liquid chromatography and preparative TLC. The isolated fractions including phosphatidylinositol dimannosides, cardiolipin, phosphatidylglycerol, phosphatidylethanolamine, trehalose monomycolate, trehalose dimycolate, and mycoside B. Trehalose dimycolate, when delivered to bone marrow-derived murine macrophages, induced the greatest secretion of IL-1beta, IL-6, and TNF-alpha in vitro. Trehalose dimycolate similarly induced the greatest secretion of these proinflammatory cytokines in ex vivo matrices over the course of 12 days. Trehalose monomycolate and dimycolate also induced profound neutrophil recruitment in vivo. Experiments with TLR2 or TLR4 gene-deficient mice revealed no defects in responses to trehalose mycolates, although MyD88-deficient mice manifested significantly reduced cell recruitment and cytokine production. These results demonstrate that the trehalose mycolates, particularly trehalose dimycolate, are the most bioactive lipids in the BCG extract, inducing a proinflammatory cascade that influences granuloma formation.

Cord factor trehalose 6,6'-dimycolate (TDM) mediates trafficking events during mycobacterial infection of murine macrophages

The persistence of tuberculosis within pulmonary granulomatous lesions is a complex phenomenon, with bacterial survival occurring in a focal region of high immune activity. In part, the survival of the organism may be linked to the ability of the surface glycolipid trehalose 6,6'-dimycolate (TDM; cord factor) to inhibit fusion events between phospholipid vesicles inside the host macrophage. At the same time, TDM contributes to macrophage activation and a cascade of events required for initiation and maintenance of granulomatous responses. This allows increased sequestration of organisms and further survival and persistence within host tissues. Bacterial viability, macrophage cytokine and chemokine response, and intracellular trafficking were investigated in Mycobacterium tuberculosis from which TDM had been removed. Removal of surface lipids led to enhanced trafficking of organisms to acidic compartments; reconstitution of delipidated organisms with either pure TDM or the petroleum ether extract containing crude surface lipids restored normal responses. Use of TDM-coated polystyrene beads demonstrated that TDM can mediate intracellular trafficking events, as well as influence macrophage production of pro-inflammatory molecules. Thus, the presence of TDM may be an important determinant for successful infection and survival of M. tuberculosis within macrophages.

A murine model of granulomatous colitis with mesenteric lymphadenitis induced by mycobacterial cord factor

Granulomatous colitis is a major entity of human intestinal diseases. We previously reported that intravenous injection of mycobacterial cord factor (CF), a potent macrophage activator, induced pulmonary granulomas in mice with enhanced production of Th1 cytokines and chemokines. In this study we made a murine model of granulomatous colitis by intramural injection of CF. A single dose of 300 microg CF was injected into the wall of the rat and mouse colon in the form of liposomes. After 1 week granulomas developed at the injection site, extending from the subserosa to the lamina propria, and persisted for longer than 6 weeks. They were composed mainly of ED1-positive macrophages, which often underwent apoptosis, and CD4(+) and CD8(+) lymphocytes, which preferentially infiltrated around the macrophage accumulation. Myofibroblast proliferation was not prominent, and no appreciable fibrosis resulted after the decline of granulomas. Although the intestinal epithelium was involved in inflammation, tissue injuries such as mucosal erosion or ulceration were not induced. When granulomas were formed near the Peyer's patches, they invaded deeply into the lymphoid tissue, producing many small islands. The mesenteric lymph nodes also had many granulomatous islands in the cortex and medulla, but the liver and spleen displayed no granulomatous changes, suggesting that liposomal CF spreads via the lymphatic vessels from the injection site. The CF-induced colonic granulomas associated with mesenteric lymphadenitis will be useful for investigating human granulomatous colitis.

Pulmonary granulomas of guinea pigs induced by inhalation exposure of heat-treated BCG Pasteur, purified trehalose dimycolate and methyl ketomycolate

This study was designed to determine the identity of granulomatogenic substances in Mycobacterium bovis BCG Pasteur. When heat-treated BCG Pasteur bacilli were introduced into the lungs of guinea-pigs by an inhalation exposure apparatus, pulmonary granulomas without necrosis developed. Furthermore, when four kinds of mycolates derived from M. tuberculosis Aoyama B strain were introduced into the lungs by the same method, only trehalose 6,6'-dimycolate (TDM) and methyl ketomycolate induced pulmonary granulomas without central necrosis. The pulmonary granulomas consisted of epithelioid macrophages and lymphocytes. When a mixture of TDM and anti-TDM antibody was introduced into the lungs, development of granulomatous lesions was reduced. These data indicate that TDM and methyl ketomycolate are potent granulomatogenic reagents.

Trehalose 6,6'-dimycolate (cord factor) of Mycobacterium tuberculosis induces foreign-body- and hypersensitivity-type granulomas in mice

Granulomatous inflammation is characterized morphologically by a compact organized collection of macrophages and their derivatives. It is classified as either a hypersensitivity type or a foreign-body type. Lipid components of the Mycobacterium tuberculosis cell wall participate in the pathogenesis of infection. Strains of M. tuberculosis have cord factor (trehalose 6,6'-dimycolate [TDM]) on their surface. To clarify host responses to TDM, including immunogenicity and pathogenicity, we have analyzed the footpad reaction, histopathology, and cytokine profiles of experimental granulomatous lesions in immunized and unimmunized mice challenged with TDM. In the present study, we have demonstrated for the first time that TDM can induce both foreign-body-type (nonimmune) and hypersensitivity-type (immune) granulomas by acting as a nonspecific irritant and T-cell-dependent antigen. Immunized mice challenged with TDM developed more severe lesions than unimmunized mice. At the active lesion, we found monocyte chemotactic, proinflammatory, and immunoregulatory cytokines. The level was enhanced in immunized mice challenged with TDM. This result implies that both nonimmune and immune mechanisms participate in granulomatous inflammation induced by mycobacterial infection. Taken together with a previous report, this study shows that TDM is a pleiotropic molecule against the host and plays an important role in the pathogenesis of tuberculosis.

Immune responses and side effects of five different oil-based adjuvants in mice

In this study, five different oil based adjuvants were compared to assess efficacy and side effects. Mice were injected subcutaneously (s.c.) or intraperitoneally (i.p.) with a weak immunogen (synthetic peptide) emulsified in Freund's adjuvant (FA), Specol, RIBI, TiterMax or Montanide ISA50. Efficacy of adjuvants was evaluated based on their properties to induce peptide specific IgG1, IgG2a and total IgG antibodies, native protein cross-reactive antibodies and cytokine production. Side effects were evaluated based on clinical and behavioural abnormalities, and (histo)pathological changes. Although marked differences in isotype profile and height of titre are observed among the different adjuvants used, we found that FA, Montanide ISA50 and Specol worked equally well in the s.c. and i.p. route, TiterMax functioned only when given i.p. and RIBI also did not perform up to par. The number of cytokine (interferon-gamma and interleukin-4) producing spleen cells was significantly higher after injection of RIBI compared with other adjuvants. Injection of FA or TiterMax resulted in severe pathological changes while after RIBI injection minimal changes were observed. In conclusion, high peptide specific antibody levels with limited side effects can be obtained by s.c. injection of peptide combined with Montanide ISA50 or Specol as alternatives to FA.

Studies on the toxic effects of quartz and a mycobacterial glycolipid, trehalose 6,6'-dimycolate

Quartz and trehalose 6,6'-dimycolate (TDM) both potentiate tuberculosis and have toxicities that depend on surface crystalline structures. Investigations were undertaken to determine if TDM can kill macrophages and produce hemolysis in a fashion similar to that of quartz and if quartz can induce granulomas similar to those induced by TDM. Trehalose 6,6'-dimycolate was spread as a molecular monolayer on the surface of tissue culture dishes adjacent to areas of uncoated plastic for comparison. Murine peritoneal macrophages were killed within hours by contact with the TDM monolayer, while those on adjacent areas of uncoated plastic remained viable and spread normally. The membranes of erythrocytes were also damaged by contact with the monolayer of TDM. This damage was inhibited by poly-2-vinyl-pyridine-N-oxide, an inhibitor of hydrogen bonding that blocks quartz induced hemolysis. These data suggest that TDM damages membranes via an adhesive mechanism similar to that of quartz. Furthermore, injections of quartz particles into mice induce acute granulomatous reactions similar to those induced by TDM. These data indicate that TDM and quartz have certain similarities in their mechanisms of action and that these similarities may be of importance in the pathogenesis of tuberculosis.

Synthetic trehalose dicorynomycolate (S-TDCM): behavioral effects and radioprotection

This study evaluated synthetic trehalose dicorynomycolate (S-TDCM), an immunomodulator, for its survival enhancing capacity and behavioral toxicity in B6D2F1 female mice. In survival experiments, mice were administered S-TDCM (25-400 micrograms/mouse i.p.) 20-24 hr before 5.6 Gy mixed-field fission-neutron irradiation (n) and gamma-photon irradiation. The 30-day survival rates for mice treated with 100-400 micrograms/mouse S-TDCM were significantly enhanced compared to controls. Toxicity of S-TDCM was measured in nonirradiated mice by locomotor activity, food intake, water consumption, and alterations in body weight. A dose-dependent decrease was noted in all behavioral measures in mice treated with S-TDCM. Doses of 100 and 200 micrograms/mouse S-TDCM significantly reduced motor activity beginning 12 hr postinjection with recovery by 24 hr. A dose of 400 micrograms/mouse significantly decreased activity within the first 4 hr after administration and returned to control levels by 32 hr following injection. Food and water intake were significantly depressed at doses of 200 and 400 micrograms/mouse on the day following drug administration, and were recovered in 24 hr. Body weight was significantly decreased in the 200 micrograms/mouse group for 2 days and in the 400 micrograms/mouse group for 4 days following injection. A dose of 100 micrograms/mouse effectively enhanced survival after fission-neutron irradiation with no adverse effect on food consumption, water intake, or body weight and a minimal, short-term effect on locomotor activity.

Granuloma formation activity and mycolic acid composition of mycobacterial cord factor

We analyzed the mycolic acid composition of trehalose 6,6'-dimycolate (TDM) obtained from Mycobacterium, using thin layer chromatography, gas chromatography and gas chromatography-mass spectrometry. Utilizing TDM, whose structure was confirmed, granuloma formation in mice was investigated. All TDM used exhibited considerable granuloma formation activity in the lung and spleen. In particular, TDM from M. bovis showed the greatest activity and toxicity among mycobacterial TDM. We therefore discussed the relationship between the chemical structure and granuloma-forming activity of TDM, especially in relation to the structure of mycolic acid in TDM.

Activation of protein kinase C by mycobacterial cord factor, trehalose 6-monomycolate, resulting in tumor necrosis factor-alpha release in mouse lung tissues

Cord factors are mycoloyl glycolipids in cell walls of bacteria belonging to Actinomycetales, such as Mycobacterium, Nocardia and Rhodococcus. They induce granuloma formation in the lung and interstitial pneumonitis, associated with production of macrophage-derived cytokines. We studied how cord factors induce biological activities in the cells. Cord factors isolated from M. tuberculosis, trehalose 6-monomycolate (mTMM) and trehalose 6,6'-dimycolate (mTDM), enhanced protein kinase C (PKC) activation in the presence of phosphatidylserine (PtdSer), diacylglycerol and Ca2+, and mTMM activated PKC alpha more strongly than PKC beta or gamma under the same assay conditions. Kinetic studies of mTMM in response to PKC activation revealed that mTMM increased the apparent affinity of PKC to Ca2+ in the presence of both PtdSer and diolein. Although this is similar to observations with unsaturated fatty acids, such as arachidonic acid, mTMM was synergistic with PtdSer for PKC activation, but arachidonic acid was not. mTMM was also different as regards PKC activation, as phorbol ester was. A single i.p. administration of mTMM to mouse induced tumor necrosis factor-alpha (TNF-alpha) in serum and in the lung, which is a unique target tissue of cord factors. Based on our recent finding that TNF-alpha is an endogenous tumor promoter, the correlation between lung cancer and pulmonary tuberculosis is discussed.

Induction of pulmonary granulomas, macrophage procoagulant activity, and tumor necrosis factor-alpha by trehalose glycolipids

Trehalose 6,6' dimycolate (TDM), a mycobacterial glycolipid, induces granulomas and hemorrhagic toxic reactions when administered in oil but not as a suspension in saline. It was previously demonstrated by us that TDM forms highly structured layers at oil-water interfaces and then postulated that its toxicity derives from the adhesive properties of these layers. To test this hypothesis, an evaluation was made of the ability of TDM and two analogs, trehalose 6-monomycolate (TMM) and galactose-galactose 6, 6' dimycolate (GDM), to induce pulmonary granulomas and stimulate expression of procoagulant activity (PCA) and tumor necrosis factor-alpha (TNF-alpha). Intravenous injection in mice of oil-in-water emulsions of TDM produced more and larger pulmonary granulomas than injection of TMM or GDM. Similarly, TDM on the surface of beads induced higher levels of PCA and TNF-alpha in human mononuclear cells than the analogs. The correlation of these results with the structure of surface layers of the glycolipids strengthens the hypothesis that the particular surface structure formed by TDM is necessary for its biologic activity.

Behavioral toxicity of selected radioprotectors

Effective radioprotection with minimal behavioral disruption is essential for the selection of protective agents to be used in manned spaceflight. This overview summarizes the studies on the behavioral toxicity of selected radioprotectors classified as phosphorothioates (WR-2721, WR-3689), bioactive lipids (16, 16 dimethylprostaglandin E2(DiPGE2), platelet activating factor (PAF), leukotriene C4), and immunomodulators (glucan, synthetic trehalose dicorynomycolate, and interleukin-1). Behavioral toxicity was examined in laboratory mice using a locomotor activity test. For all compounds tested, there was a dose-dependent decrease in locomotor behavior that paralleled the dose-dependent increase in radioprotection. While combinations of radioprotective compounds (DiPGE2 plus WR-2721) increased radioprotection, they also decreased locomotor activity. The central nervous system stimulant, caffeine, was able to mitigate the locomotor decrement produced by WR-3689 or PAF.

Chemical synthesis and biological activities of 6,6'-di-O-mycoloyl-beta,beta- and -alpha,beta-trehalose

6,6'Di-O-mycoloyl-beta,beta-trehalose (beta,beta-TDM) and 6,6'-di-O-mycoloyl-alpha,beta-trehalose (alpha,beta-TDM) were synthesized and their toxicity and ability to activate peritoneal macrophages in situ were examined in mice, in comparison with 6,6'-di-O-mycoloyl-alpha,alpha-trehalose (TDM). Both beta,beta-TDM and alpha,beta-TDM caused a decrease in body weight two days after injection, however the weights reverted to a normal level. No deaths were caused by either analog. On the other hand, TDM showed potent toxicity, causing decrease in body weight and death of all animals injected. Beta,beta-TDM and alpha,beta-TDM were effective in the in situ activation of mouse peritoneal macrophages.

Lethal toxicity and adjuvant activities of synthetic TDM and its related compounds in mice

Trehalose-6,6'-dimycolate (TDM) and its monosaccharide-type analogues were synthesized, and their lethal and adjuvant activities were examined in mice. All the monosaccharide-type analogues with a glucose or N-acetylglucosamine moiety were devoid of lethal toxicity to mice; in particular, D-GlcNAcM(1-deoxy) and D-GlcNM did not cause any loss of body weight at an early stage after intravenous administration as a 9% oil-in-water emulsion. Intraperitoneal administration of D-GlcNAcM(1-deoxy) in aqueous suspension, as well as TDM, could activate macrophages to become tumoricidal against tumour cells, whereas D-GlcNAcM(1-deoxy) in oil emulsion, unlike TDM, caused no granulomatous formation in the lung after intravenous injection. Squalane-treated D-GlcNAcM(1-deoxy) showed significant inhibition of spontaneous lung metastases by B16-BL6 melanoma cells when it was administered twice intratumorally. The non-toxic monosaccharide-type analogue of TDM [D-GlcNAcM(1-deoxy)] was a beneficial adjuvant for the activation of macrophages and the prevention of cancer metastasis.

Mechanisms of pathogenicity in mycobacteria

The purpose of this article is to review current knowledge about the mechanisms of pathogenicity of mycobacteria. The following aspects of the problem are discussed: chemically-defined compounds implicated in the mechanisms of pathogenicity; location in the cell wall of these compounds and their biological activities; mechanisms of intracellular survival of pathogenic mycobacteria as compared to intracellular killing of non-pathogenic mycobacteria; and pathogenesis of mycobacterial infection. The future prospects in the elucidation of the mechanisms of pathogenicity and their possible application for a better control of mycobacterial diseases are briefly discussed.

Dissemination of beads coated with trehalose 6,6'-dimycolate: a possible role for coagulation in the dissemination process

When spread as a monolayer on the surface of hydrophobic beads and injected into mice, the mycobacterial glycolipid, trehalose 6,6'-dimycolate, reproduces the biologic effects traditionally associated with virulent mycobacteria, including acute inflammation, granuloma formation, and immune adjuvancy. Repeated intraperitoneal injection of glycolipid-coated beads into young C57Bl/6 mice elicits a granulomatous peritonitis, with concomitant dissemination of beads from the peritoneum to distant organs. Glycolipid-coated beads which disseminate from the peritoneum to other sites elicit neither acute inflammation nor granulomata. The coagulation system may be involved in the dissemination of glycolipid-coated beads as evidenced by the following: fibrinogen is a necessary cofactor of the trehalose dimycolate monolayer; diffuse peritoneal and pulmonary hemorrhage accompanies bead dissemination; peritoneal exudate collected shortly after intraperitoneal injection of glycolipid-coated beads is enriched in coagulant activity; coagulability of blood from trehalose dimycolate-treated animals is reduced; and anticoagulation inhibits the inflammatory response to glycolipid-coated beads. In this report, the dissemination of trehalose dimycolate-coated beads is characterized, and a role for the coagulation system in this process is proposed.

Effect of cord factor, a toxic glycolipid from Mycobacterium tuberculosis, on mouse liver drug metabolizing enzymes

Cord factor (a mycobacterial toxin) treatment of mice for 72 hr resulted in decreased activities of hepatic drug metabolizing enzymes. The toxin treated animals exhibited reduced levels of liver cytochrome P-450 and cytochrome b5, accompanied by significant lowering of NADPH-cytochrome c reductase and NADH-cytochrome b5 reductase activities. The hepatic activities of aminopyrine N-demethylase and aniline hydroxylase were diminished, while liver cytosolic glutathione S-transferase activity was inhibited in mice receiving the toxin. Earlier studies from this laboratory (J. K. Batra, Ph.D. Thesis, Delhi University, India, 1982) on the effects of experimental tuberculosis on hepatic drug metabolism revealed changes similar to the presently reported influence of cord factor on mouse liver microsomal monooxygenases. Thus, the action of cord factor (on hepatic drug metabolism) largely mimics the effects of tuberculosis infection.

The pathogenesis of interstitial pneumonitis induced by trehalose dimycolate. II. Reserpine prevents formation of lesions

A single intraperitoneal injection of 10 micrograms of trehalose dimycolate (TDM) produced interstitial and hemorrhagic pneumonitis in C57BL/6 mice. As a part of an investigation of a possible role for cell-mediated immunity in the pathogenesis of this disorder, we found that reserpine, 3 mg/kg, given before, at the same time, or on Day 5 after administration of TDM, significantly reduced development of interstitial pneumonitis by Day 7. Smaller doses were less effective. Administration of reserpine, 3 or 2 mg/kg, 1 to 3 days after administration of TDM was lethal to most mice. Reserpine has been shown to inhibit expression of cell-mediated immune responses in mice, probably by causing intercellular release and degradation of vasoactive amines. Inhibition of pulmonary lesions by reserpine in TDM-treated mice suggests that a similar mechanism may be involved in the pathogenesis of TDM-induced lung injury.

Enhancement of endotoxic shock by N-acetylmuramyl-L-alanyl-(L-seryl)-D-isoglutamine (muramyl dipeptide)

We described elsewhere that the synergistic antitumor activity of endotoxic extracts from Re mutants of gram-negative bacteria and trehalose mycolate against guinea pig syngeneic line 10 tumor was abrogated after peptide substances accompanying these extracts had been removed. This activity could be restored by combining peptide-free endotoxin either with cell wall skeleton from Bacillus Calmette-Guérin, a polymeric mycolic acid-arabinogalactan-mucopeptide complex, or with a combination of two separate components, trehalose dimycolate and N-acetylmuramyl-L-alanyl-(L-seryl)-D-isoglutamine (MDP). We report here that when a combination of endotoxin (150 microgram) and a mixture of MDP (150 microgram) and trehalose dimycolate (150 microgram) was inoculated into established dermal tumors, a significant number of the animals died, presumably of endotoxic shock. All surviving animals suffered severe but temporary lethargy. When administered alone intradermally in the dose levels tested, none of the components caused severe lethargy or lethality. The lethal effects of 159 microgram of MDP also occurred in combination with relatively weak endotoxic products, such as Pseudomonas vaccine (Pseudogen), and these effects did not depend upon the presence of malignant tissue. Guinea pigs inoculated i.v. were even more susceptible inasmuch as the addition of as little as 6 microgram of MDP to 150 microgram of Pseudogen, itself not lethal, caused the death of 80% of the animals.

Regression of a murine fibrosarcoma after intralesional injection of a synthetic C39 glycolipid related to cord factor

Intratumoral injection of ultrasonically prepared emulsions of the synthetic glycolipid methly 6-O-(2-tetradecyl-3-hydroxyoctadecanoyl)-alpha-D-glucopyranoside (designated C39) induced complete regression of transplants of a syngeneic murine fibrosarcoma in most of the treated animals as did 6,6'-di-O(2-tetradecyl-3-hydroxyoctadecanoyl)-alpha,alpha,-trehalose (designated C76) in a previous study. The C76 compound, about twice the molecular weight of C39, was more effective therapeutically than the smaller molecule. Ultrasonically prepared emulsions of C39 and C76 were not toxic when given intravenously. Intravenously administered emulsions of C39 prepared by mechanical grinding were more toxic, but less granulomagenic, than those containing C76. Squalane and squalene, but not peanut oil, were effective substitutes for mineral oil as carriers of C39 in the treatment of the tumor.

Pseudo cord factors: derivatives of alpha-D-glucopyranuronosyl (1-1) alpha-D-glucopyranuronoside

We describe the synthesis of 6 pseudo cord factors (psi CF), analogs of the natural trehalose-6,6'-dimycolate, but based instead upon the dicarboxylic acid (TDA) that is obtained from trehalose by Pt-catalyzed oxidation. From TDA, several bis-amides ('mirror amide' psi CF) and a diester ('mirror' psi CF) of intermediate to high molecular weight were prepared. These superficially resemble cord facotr, have similar infared spectra and, like the natural product, several have impressive toxicity in mice and tumor-regression activity; but the latter property does not depend upon the former. A curious abrogation of biological activities results from introduction of a hexamethylene diamine 'spacer' between the carbohydrate core and the lipid substituents. The results suggest that (excepting the 'spacer' effect) the type of covalent linkage between the carbohydrate and lipid moieties may be relatively unimportant for expression of some of the biological activities of cord-factor-like glycolipids.

Effect of sulfolipid I on trehalose-6,6'-dimycolate (cord factor) toxicity and antitumor activity

Emulsified mixtures of sulfolipid I and trehalose-6,6'-dimycolate (cord factor) had tumor-regressive activity comparable to, but less toxic than, emulsified trehalose-6,6'-dimycolate alone.

Toxicity of emulsified trehalose-6,6'-dimycolate (cord factor) in mice depends on size distribution of mineral oil droplets

Toxicity of emulsified trehalose-6,6'-dimycolate administered intravenously into mice depended on the size distribution of the mineral oil droplets. Emulsions containing the greatest number of the largest oil droplets were the most toxic. Emulsions of trehalose-6,6'-dimycolate made with peanut oil or with olive oil were less toxic than those made with mineral oil.

Cord factor not toxic in rats

Systemic toxicity and local inflammatory activity of cord factor were compared between mice and rats. In mice, repeated intraperitoneal injection of cord factor caused a marked worsening of general condition and high mortality. The swelling of footpads injected with cord factor was also marked in mice. In contrast, injection of cord factor produced no such toxic reactions in rats, except that repeated intraperitoneal injections of high doses of cord factor induced an accumulation of ascites.

The adjuvant activity of a non-toxic, water-soluble glycopeptide present in large quantities in the culture filtrate of Mycobacterium tuberculosis strain DT

A water-soluble mycobacterial glycopeptide was obtained in large quantities from the culture supernatant fluid of M. tuberculosis strain DT. This glycopeptide was strongly adjuvant-active when injected, in a water-in-oil emulsion contianing ovalbumin, into guinea-pigs. In addition, it was devoid of cord factor toxicity in mice, polyarthritogenic activity in rats and cavity stimulating activity in rabbit lungs.