In vitro and in vivo interactions of Haemophilus ducreyi with host phagocytes
| Autor: | Hinda J. Ahmed, Catharina Johansson, Karin Ahlman, Liselott A. Svensson, Margareta Verdrengh, Teresa Lagergård |
|---|---|
| Rok vydání: | 2002 |
| Předmět: |
Sexually transmitted disease
Injections Intradermal Phagocytosis Immunology Mice SCID Biology Granulocyte urologic and male genital diseases Microbiology Monocytes Chancroid Haemophilus ducreyi Mice Skin Ulcer medicine Macrophage Animals Humans Opsonin Cells Cultured Mice Inbred BALB C Cellular Microbiology: Pathogen-Host Cell Molecular Interactions integumentary system Monocyte Opsonin Proteins biology.organism_classification bacterial infections and mycoses female genital diseases and pregnancy complications Antibody opsonization Disease Models Animal Infectious Diseases medicine.anatomical_structure bacteria Parasitology Female Granulocytes |
| Zdroj: | Infection and immunity. 70(2) |
| ISSN: | 0019-9567 |
| Popis: | We investigated the phagocytosis of Haemophilus ducreyi both in vitro and in vivo. Human granulocyte and monocyte phagocytosis of opsonized and nonopsonized, fluorescence-labeled H. ducreyi was assessed by flow cytometry. Both Escherichia coli and noncapsulated H. influenzae were included as controls. The maximal percentage of granulocytes taken up by H. ducreyi was 35% after 90 min. In contrast, 95% of H. influenzae bacteria were phagocytosed by granulocytes after 30 min. These results indicated that H. ducreyi phagocytosis was slow and inefficient. Bacterial opsonization by using specific antibodies increased the percentage of granulocytes phagocytosing H. ducreyi from 24 to 49%. The nonphagocytosed bacteria were completely resistant to phagocytosis even when reexposed to granulocytes, indicating that the H. ducreyi culture comprised a mixture of phenotypes. The intracellular survival of H. ducreyi in granulocytes, in monocytes/macrophages, and in a monocyte cell line (THP-1) was quantified after application of gentamicin treatment to kill extracellular bacteria. H. ducreyi survival within phagocytes was poor; approximately 11 and H. influenzae bacteria were recovered after 2 h of incubation with phagocytes. The role of phagocytes in the development of skin lesions due to H. ducreyi was also studied in vivo. Mice that were depleted of granulocytes and/or monocytes and SCID mice, which lacked T and B cells, were injected intradermally with approximately 10 6 CFU of H. ducreyi . Within 4 days of inoculation, the granulocyte-depleted mice developed lesions that persisted throughout the experimental period. This result reinforces the importance of granulocytes in the early innate defense against H. ducreyi infection. In conclusion, H. ducreyi is insufficiently phagocytosed to achieve complete eradication of the bacteria. Indeed, H. ducreyi has the ability to survive intracellularly for short periods within phagocytic cells in vitro. Since granulocytes play a major role in the innate defense against H. ducreyi infection in vivo, bacterial resistance to phagocytosis probably plays a crucial role in the pathogenesis of chancroid. |
| Databáze: | OpenAIRE |
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