RESUMEN
Actinobacillus actinomycetemcomitans leukotoxin lysed human neutrophil cytoplasts. The reaction was associated with a rapid influx of extracellular calcium, a collapse in membrane potential, release of lactate dehydrogenase, and overt disintegration of the plasma membrane. These functional and structural alterations in the plasmalemma of neutrophil cytoplasts reinforce the hypothesis that A. actinomycetemcomitans leukotoxin acts as a pore-forming, membranolytic agent and indicate that neutrophil cytoplasts are useful tools in studying the biology of membrane-active toxins.
Asunto(s)
Aggregatibacter actinomycetemcomitans/patogenicidad , Toxinas Bacterianas/toxicidad , Citotoxinas/toxicidad , Exotoxinas/toxicidad , Neutrófilos/efectos de los fármacos , Calcio/metabolismo , Humanos , Técnicas In Vitro , L-Lactato Deshidrogenasa/metabolismo , Potenciales de la Membrana/efectos de los fármacos , Neutrófilos/metabolismo , Neutrófilos/ultraestructuraRESUMEN
Vascular endothelial growth factor (VEGF) is a multifunctional cytokine that plays a pivotal role in mediating neovascularization as well as other endothelial cell alterations during inflammation. In this study, we demonstrate that human neutrophils are a source of VEGF. We observed that isolated blood neutrophils released VEGF in response to different stimuli and we demonstrated by immunohistochemistry that neutrophils infiltrating inflamed tissues contain VEGF. These results indicate that neutrophil-derived VEGF may be instrumental in regulating vascular responses during acute and chronic inflammation.
Asunto(s)
Factores de Crecimiento Endotelial/metabolismo , Linfocinas/metabolismo , Neutrófilos/metabolismo , Adulto , Western Blotting , Células Cultivadas , Femenino , Humanos , Inmunohistoquímica , Ionomicina/farmacología , Ionóforos/farmacología , Masculino , Persona de Mediana Edad , Mucosa Bucal/citología , Forbol 12,13-Dibutirato/farmacología , Factor A de Crecimiento Endotelial Vascular , Factores de Crecimiento Endotelial Vascular , ZimosanRESUMEN
A soluble extract from Actinobacillus actinomycetemcomitans (designated strain Y4) caused dose-dependent cytotoxic changes in PMN isolated from the gingival crevices (C-PMN) of normal adults. When the toxin was preincubated with sera from patients with juvenile periodontitis, there was a significant inhibition of toxic activity. In contrast a variety of other sera from normal subjects with healthy gingiva, and from patients with chronic gingivitis, chronic periodontitis, recurrent herpes labialis, rheumatoid arthritis, or ulcerative colitis enhanced the leukotoxic activity. The neutralization of toxin by serum from patients with juvenile periodontitis was probably due to specific antibodies. Since Actinobacillus actinomycetemcomitans organisms can be frequently identified in subgingival plaque from patients with juvenile periodontitis, the capacity of Y4 toxin to kill C-PMN may contribute to the pathogenesis of this disease.
Asunto(s)
Infecciones por Actinobacillus/etiología , Exotoxinas/farmacología , Enfermedades de las Encías/etiología , Neutrófilos/fisiopatología , Adulto , Animales , Artritis Reumatoide/fisiopatología , Enfermedad Crónica , Colitis Ulcerosa/fisiopatología , Enfermedad de Crohn/fisiopatología , Medios de Cultivo , Exotoxinas/antagonistas & inhibidores , Herpes Labial/fisiopatología , Humanos , Pruebas de Neutralización , Periodontitis/etiología , ConejosRESUMEN
Human parotid saliva contains agglutinins which bind to the surface of streptococci and induce the formation of bacterial aggregates. Bacterial aggregation can be blocked by proteins released from viable PMNs and platelets or by sonic extracts prepared from these cells. PMN and platelet inhibitors display characteristic differences in molecular weight, protease, and temperature sensitivity. The mechanism of action of the inhibitors appears to involve a direct interaction with the salivary agglutinins rather than with the bacteria. It is thus possible that PMN and platelet-derived products might modulate saliva-mediated bacterial aggregation and thereby influence the course of infections in the oral cavity.
Asunto(s)
Plaquetas/inmunología , Neutrófilos/inmunología , Saliva/inmunología , Streptococcus mutans/inmunología , Streptococcus sanguis/inmunología , Aglutininas/inmunología , Humanos , Activación de Linfocitos , SonicaciónRESUMEN
Isolated human peripheral blood neutrophils were exposed to sonic extracts of Actinobacillus actinomycetemcomitans. Such bacterial preparations contain a potent leukotoxin which rapidly kills the leukocytes as reflected by cellular uptake of trypan blue, extracellular release of lactate dehydrogenase, or discharge of 51Cr from pre-labeled cells. Exogenous phospholipids with a glycerol skeleton esterified by fatty acids or positively charged liposomes inhibited cytotoxic phenomena. The data suggest that cell damage may involve the interaction of leukotoxin with phospholipids in the neutrophil cell membrane and that exogenous lipids either compete for or sterically block binding of the leukotoxin to these moieties in the membrane.
Asunto(s)
Actinobacillus/análisis , Citotoxicidad Inmunológica/efectos de los fármacos , Exotoxinas/farmacología , Neutrófilos/efectos de los fármacos , Fosfolípidos/farmacología , Exotoxinas/análisis , Humanos , Liposomas/farmacologíaRESUMEN
Eighteen (18) members of an extended family in which numerous individuals have Papillon-Lefèvre syndrome (PLS) were examined. In all, 6 affected members and 12 non-affected members were included. All patients underwent a clinical examination which, in the dentate persons, included plaque index, bleeding on probing, probing depth, and periodontal attachment loss and a set of full mouth periapical x-rays. Subgingival bacterial samples were also collected from 2 teeth in the dentate patients for cultures and identification of Actinobacillus actinomycetemcomitans. Serum samples were collected from all participants and assayed for antileukotoxin antibodies. The results indicate that there is a high prevalence of leukotoxic strains of A. actinomycetemcomitans in persons suffering from PLS, as well as in unaffected family members. The ubiquitous presence of A. actinomycetemcomitans in the family units suggests a close association between A. actinomycetemcomitans and the periodontal disease associated with the syndrome; it also suggests that A. actinomycetemcomitans by itself is not sufficient for the expression of periodontal disease and that other factors, some of which must be genetic, are necessary for lesion development.
Asunto(s)
Aggregatibacter actinomycetemcomitans/inmunología , Aggregatibacter actinomycetemcomitans/aislamiento & purificación , Anticuerpos Antibacterianos/análisis , Toxinas Bacterianas/inmunología , Citotoxinas/inmunología , Exotoxinas/inmunología , Enfermedad de Papillon-Lefevre/genética , Adolescente , Adulto , Bacterias/aislamiento & purificación , Preescolar , Recuento de Colonia Microbiana , Índice de Placa Dental , Femenino , Hemorragia Gingival/inmunología , Hemorragia Gingival/microbiología , Hemorragia Gingival/patología , Humanos , Masculino , Persona de Mediana Edad , Enfermedad de Papillon-Lefevre/inmunología , Enfermedad de Papillon-Lefevre/microbiología , Pérdida de la Inserción Periodontal/inmunología , Pérdida de la Inserción Periodontal/microbiología , Pérdida de la Inserción Periodontal/patología , Enfermedades Periodontales/inmunología , Enfermedades Periodontales/microbiología , Enfermedades Periodontales/patología , Bolsa Periodontal/inmunología , Bolsa Periodontal/microbiología , Bolsa Periodontal/patologíaAsunto(s)
Enfermedades Periodontales/etiología , Complejo Antígeno-Anticuerpo , Placa Dental/inmunología , Placa Dental/microbiología , Exudados y Transudados , Humanos , Activación de Linfocitos , Enfermedades Periodontales/inmunología , Enfermedades Periodontales/metabolismo , Enfermedades Periodontales/microbiologíaAsunto(s)
Pulpa Dental/fisiopatología , Gingivitis/fisiopatología , Inflamación , Lisosomas/metabolismo , Neutrófilos/metabolismo , Enfermedades Periodontales/inmunología , Periodontitis/fisiopatología , Animales , Bacterias/inmunología , Placa Dental/inmunología , Enfermedades de la Pulpa Dental/inmunología , Humanos , Técnicas In Vitro , ConejosAsunto(s)
Fenómenos Fisiológicos Bacterianos , Placa Dental/microbiología , Hidrolasas/metabolismo , Leucocitos/enzimología , Lisosomas/enzimología , Actinomyces/fisiología , Animales , Bacterias/citología , Catepsinas/metabolismo , Recuento de Células , Femenino , Glucuronidasa/metabolismo , Técnicas In Vitro , Leucocitos/citología , Muramidasa/metabolismo , Conejos , Streptococcus mutans/fisiología , Streptococcus sanguis/fisiologíaAsunto(s)
Absceso/etiología , Placa Dental , Inflamación/etiología , Leucopenia/inducido químicamente , Boca , Fagocitosis , Animales , Recuento de Células Sanguíneas , Humanos , Inflamación/patología , Inyecciones Intradérmicas , Compuestos de Mostaza Nitrogenada/farmacología , Conejos , Sepsis/patología , Heridas y Lesiones/patologíaAsunto(s)
Actinobacillus/inmunología , Exotoxinas , Periodontitis/microbiología , Adulto , Antígenos Bacterianos/inmunología , Citotoxicidad Inmunológica , Epítopos , Exotoxinas/inmunología , Humanos , Inmunodifusión , Técnicas In Vitro , L-Lactato Deshidrogenasa/metabolismo , Neutrófilos/inmunologíaAsunto(s)
Catepsinas/metabolismo , Galactosidasas/metabolismo , Glucuronidasa/metabolismo , Rechazo de Injerto , Animales , Catepsinas/análisis , Trasplante de Córnea , Modelos Animales de Enfermedad , Galactosidasas/análisis , Glucuronidasa/análisis , Cobayas , Conejos , Factores de Tiempo , Trasplante HeterólogoRESUMEN
Juvenile periodontitis is associated with a high incidence of infection by Actinobacillus actinomycetemcomitans (Aa). The data presented indicate that the ability of Aa to destroy human PMNs is altered during the course of infection. Leukotoxic strains of Aa are characteristically found in isolates obtained from younger patients (6-12 years of age) but not in older subjects (13-25 years old). This suggests that the leukotoxin may be more important during early as opposed to more advanced phases of juvenile periodontitis.
Asunto(s)
Actinobacillus/fisiología , Periodontitis Agresiva/microbiología , Citotoxinas/farmacología , Leucocitos/efectos de los fármacos , Enfermedades Periodontales/microbiología , Actinobacillus/inmunología , Infecciones por Actinobacillus/fisiopatología , Adolescente , Adulto , Factores de Edad , Periodontitis Agresiva/inmunología , Periodontitis Agresiva/fisiopatología , Anticuerpos Antibacterianos/análisis , Niño , Citotoxinas/inmunología , Humanos , Leucocitos/inmunologíaRESUMEN
The release of lysosomal hydrolases from polymorphonuclear leukocytes (PMNs) has been postulated in the pathogenesis of tissue injury in periodontal disease. In the present study, lysosomal enzyme release was monitored from rabbit peritoneal exudate PMNs exposed to Streptocccus mutans or Streptococcus sanguis. S. mutans grown in brain heart infusion (BHI) broth failed to promote significant PMN enzyme release. S. sanguis grown in BHI broth, although more effective than S. mutants, was a weak stimulus for promotion of PMN hydrolase release. Preincubation of washed, viable S. mutans in sucrose or in different-molecular-weight dextrans resulted in the ability of the organisms to provoke PMN release reactions. This effect could bot be demonstrated with boiled or trypsinized S. mutans or with viable S. sanguis. However, when grown in BHI broth supplemented with sucrose, but not with glucose, both S. mutans and S. sanguis triggered discharge of PMN enzymes. The mechanism(s) whereby dextran or sucrose modulates PMN-bacterial interaction may in some manner be related to promotion of microbial adhesiveness or aggregation by dextran and by bacterial synthesis of glucans from sucrose.
Asunto(s)
Neutrófilos/enzimología , Polisacáridos/farmacología , Streptococcus mutans , Streptococcus sanguis , Streptococcus , Animales , Sistema Libre de Células , Medios de Cultivo , Dextranos/farmacología , Hidrolasas/metabolismo , Conejos , Streptococcus mutans/crecimiento & desarrollo , Sacarosa/farmacologíaRESUMEN
A potent, heat-labile leukotoxic material was extracted from Actinobacillus actinomycetemcomitans (strain Y4), an anaerobic gram-negative microorganism originally isolated from subgingival plaque in a patient with juvenile periodontitis. The cytopathic effects of Y4 toxin on purified monocytes were studied by the extracellular release of radioactive cytoplasmic markers and cell enzymes and by time-lapse microcinematography. Y4 toxin rapidly bound to the cells, producing dose- and time-dependent alterations culminating in cell death and release of intracellular constituents into the culture medium. The evidence to be presented suggests that the cell membrane of the monocyte may be the primary target in the development of these phenomena. Previous studies have shown that Y4 toxin also kills human polymorphonuclear leukocytes but not other cell types. It is conceivable that disruption of polymorphonuclear leukocytes and monocytes by Y4 toxin in the gingival crevice area may be relevant in the pathogenesis of juvenile periodontitis.
Asunto(s)
Actinobacillus , Toxinas Bacterianas/farmacología , Citotoxinas/farmacología , Monocitos/citología , Antiinflamatorios/farmacología , Carbohidratos/farmacología , Membrana Celular/fisiología , Citocalasina B/farmacología , Dextranos/farmacología , Heparina/farmacología , Humanos , Monocitos/metabolismo , Albúmina Sérica Bovina/farmacologíaRESUMEN
The purified leukotoxin of Actinobacillus actinomycetemcomitans kills human leukemic cell lines (e.g., HL-60, U937, and KG-1) and human T- and B-cell lines (e.g., JURKAT, MOLT-4, Daudi, and Raji) in a dose- and time-dependent manner. The 50% effective doses for these cell lines are similar to those established for human polymorphonuclear leukocytes and monocytes. In contrast, other human and nonhuman tumor cell lines are not susceptible to the leukotoxin. These human leukemia and lymphoid cell lines will serve as useful model systems with which to study the molecular specificity and mechanism(s) of action of the actinobacillus leukotoxin.
Asunto(s)
Actinobacillus/patogenicidad , Exotoxinas/toxicidad , Leucemia Mieloide/terapia , Linfocitos T Citotóxicos/efectos de los fármacos , Animales , Supervivencia Celular/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Humanos , Inmunoterapia , Ratones , Microscopía Electrónica , Ratas , Células Tumorales CultivadasRESUMEN
The leukotoxin of Actinobacillus actinomycetemcomitans has been implicated in the pathogenesis of inflammatory periodontal disease. We examined a potential mechanism for detoxification of this microbial product by the neutrophil myeloperoxidase system. Exposure to myeloperoxidase, H2O2, and a halide resulted in marked inactivation of leukotoxin, an effect which required each component of the myeloperoxidase system. Toxin inactivation was blocked by agents which inhibit heme enzymes (azide, cyanide) or degrade H2O2 (catalase). Reagent H2O2 could be replaced by the peroxide-generating enzyme system glucose oxidase plus glucose. The latter system, in fact, was more potent than reagent H2O2 in terms of the capacity to inactivate high concentrations of toxin. Toxin inactivation was complete within 1 to 2 min at 37 degrees C. These observations suggest a possible role for oxidative inactivation of leukotoxin by secretory products of neutrophils.