Lethal effects of Actinobacillus actinomycetemcomitans leukotoxin on human T lymphocytes
| Autor: | D F Mangan, Sharon M. Wahl, N S Taichman, E T Lally |
|---|---|
| Rok vydání: | 1991 |
| Předmět: |
Programmed cell death
Necrosis Cell Survival T-Lymphocytes Bacterial Toxins Immunology Exotoxins Microbiology Leukocyte Count chemistry.chemical_compound Immune system medicine Humans Secretion Propidium iodide biology Cytotoxins Actinobacillus T lymphocyte biology.organism_classification Kinetics Infectious Diseases chemistry Apoptosis Electrophoresis Polyacrylamide Gel Parasitology medicine.symptom DNA Damage Propidium Research Article |
| Zdroj: | Infection and Immunity. 59:3267-3272 |
| ISSN: | 1098-5522 0019-9567 |
| Popis: | The majority of strains of Actinobacillus actinomycetemcomitans isolated from patients with periodontal diseases secrete a leukotoxin that destroys human myeloid cells within minutes but has no effect on viability of peripheral blood lymphocytes in culture for 1.5 h. However, since this organism persists in the gingival crevice and thus may continuously release toxin over extended periods of time, we assessed the viability of T cells cultured with leukotoxin (0 to 250 ng/ml) for up to 2 days. Although the total numbers of cells recovered from cultures with or without leukotoxin were equivalent, leukotoxin killed up to 70% of the T cells in a time- and concentration-dependent manner. Cell death was associated with uptake of propidium iodide, release of 51Cr from the cytoplasm, and morphological evidence of damage to the plasma membrane and apoptosis. Leukotoxin also induced increased cleavage of chromosomal DNA into nucleosome-sized fragments, suggesting activation of an endogenous nuclease in the T cells. These data suggest that leukotoxin kills T cells by pathways resembling necrosis and programmed cell death. Leukotoxin-induced lymphotoxicity may represent a critical mechanism by which A. actinomycetemcomitans suppresses the host local immune response and contributes to the pathogenesis of diseases involving this microorganisms. |
| Databáze: | OpenAIRE |
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