RESUMEN
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.
Asunto(s)
Factores Cordón/toxicidad , Granuloma/etiología , Enfermedades Pulmonares/etiología , Mycobacterium bovis/patogenicidad , Ácidos Micólicos/toxicidad , Administración por Inhalación , Animales , ADN Bacteriano/análisis , Femenino , Cobayas , Pulmón/patología , Mycobacterium bovis/inmunologíaRESUMEN
Trehalose 6,6'-dimycolate (TDM) is a cell surface molecule of Mycobacterium tuberculosis. TDM induced a loss of body weight and prominent granulomas in the liver and lungs by the intravenous injection of TDM into rabbits. TDM also induced atrophy of the thymus and spleen due to apoptosis. By contrast, sulfolipid (2,3,6, 6'-tetraacyl trehalose 2'-sulfate) induced neither toxicity, nor granuloma formation, nor atrophy of the thymus and spleen. In rabbits the histopathological changes were more dramatic than in mice. The rabbit model may be more sensitive and may provide more information on the beneficial or pathological effects of TDM.
Asunto(s)
Factores Cordón/farmacología , Granuloma/inducido químicamente , Hígado/efectos de los fármacos , Pulmón/efectos de los fármacos , Ácidos Micólicos/toxicidad , Timo/efectos de los fármacos , Trehalosa/análogos & derivados , Animales , Apoptosis , Atrofia/inducido químicamente , Peso Corporal/efectos de los fármacos , Factores Cordón/química , Femenino , Glucolípidos/toxicidad , Granuloma del Sistema Respiratorio/inducido químicamente , Lípidos/toxicidad , Hígado/patología , Pulmón/patología , Conejos , Bazo/efectos de los fármacos , Bazo/patología , Timo/patología , Trehalosa/toxicidadRESUMEN
Mycoloyl glycolipids cause granulomas in the lungs, liver, and spleen of mice, but the mechanism is not fully understood. To understand the role of macrophage chemotactic factors (MCFs) in granuloma formation, we prepared various mycoloyl glycolipids with different carbohydrate moieties: trehalose dimycolate (TDM), glucose mycolate (GM), mannose mycolate (MM), and fructose mycolate (FM) from Rhodococcus ruber, and examined the relationship between their MCF induction in peritoneal macrophages and the extent of granuloma formation. The molecular mass of each glycolipid was confirmed by fast-atom-bombardment mass-spectrometry. TDM or GM caused granulomas in the lungs, spleen, and liver of ICR mice, but MM and FM did not. The culture supernatant of peritoneal macrophages stimulated with TDM or GM increased macrophage migration, whereas MM and FM had no chemotactic activity. The activity of interleukin-1 (IL-1) in the supernatant was increased equally by each glycolipid and was therefore not related to chemotaxis. Tumor necrosis factor-alpha (TNF-alpha) and granulocyte-macrophage colony-stimulating factor (GM-CSF) were not detected in the four supernatants. The TDM-induced MCF was heat-stable, trypsin-labile, and undialyzable. Furthermore, we separated two MCF active fractions from the supernatant of TDM-stimulated macrophages by gel filtration. These factors acted on macrophages but not on neutrophils. Our results suggested that macrophages recognize the sugar moieties of mycoloyl glycolipids and may, in response, generate a MCF that may play an important role in the macrophage or monocyte recruitment which is essential prior to granuloma formation.
Asunto(s)
Factores Quimiotácticos/biosíntesis , Glucolípidos/toxicidad , Granuloma/fisiopatología , Macrófagos Peritoneales/fisiología , Ácidos Micólicos/toxicidad , Nocardia , Rhodococcus , Animales , Células Cultivadas , Glucolípidos/aislamiento & purificación , Factor Estimulante de Colonias de Granulocitos y Macrófagos/análisis , Granuloma/inducido químicamente , Interleucina-1/biosíntesis , Hígado/efectos de los fármacos , Hígado/patología , Pulmón/efectos de los fármacos , Pulmón/patología , Macrófagos Peritoneales/efectos de los fármacos , Masculino , Ratones , Ratones Endogámicos C3H , Ratones Endogámicos ICR , Ácidos Micólicos/aislamiento & purificación , Espectrometría de Masa Bombardeada por Átomos Veloces , Bazo/efectos de los fármacos , Bazo/patología , Factores de Tiempo , Factor de Necrosis Tumoral alfa/biosíntesisAsunto(s)
Glucolípidos/farmacología , Nocardia/análisis , Animales , Factores Biológicos/biosíntesis , Factores Estimulantes de Colonias/biosíntesis , Citocinas , Glucolípidos/toxicidad , Granuloma/inducido químicamente , Interleucina-1/biosíntesis , Ratones , Ratones Endogámicos , Ácidos Micólicos/farmacología , Ácidos Micólicos/toxicidad , Relación Estructura-ActividadAsunto(s)
Disacáridos/toxicidad , Glucolípidos/toxicidad , Mycobacterium tuberculosis/análisis , Animales , Fenómenos Químicos , Química , Metilglicósidos/toxicidad , Mitocondrias/efectos de los fármacos , Ácidos Micólicos/toxicidad , Fosforilación Oxidativa/efectos de los fármacos , Consumo de Oxígeno/efectos de los fármacos , Trehalosa/análisis , Trehalosa/toxicidadRESUMEN
A monoester of trehalose linked at the 6-position with mycolic acids (trehalose-6-monomycolate) was isolated from the wax D fraction of virulent human Mycobacterium tuberculosis, and its biochemical action on host-cell mitochondria was studied. Trehalose-6-monomycolate showed a delayed toxicity for mice. The 50% lethal dose at 2 weeks was 452 mug. It induced in vitro a swelling of mouse liver mitochondria and uncoupled respiration and phosphorylation in the nicotinamide adenine dinucleotide pathway of the electron transport chain. The site of functional damage was located specifically at coupling site II. Mitochondrial adenosine triphosphatase was slightly stimulated by trehalose-6-monomycolate. These findings indicate that trehalose-6-monomycolate affects mitochondrial oxidative phosphorylation in a similar manner to, but to a lesser extent than, trehalose-6, 6'-dimycolate (cord factor) of M. tuberculosis.