Lysozyme M deficiency leads to an increased susceptibility to Streptococcus pneumoniae-induced otitis media
| Autor: | Haa Yung Lee, Jun Shimada, Tamotsu Takeshita, David J. Lim, Robert Gellibolian, Sung Kyun Moon, Huiqi Pan, Jeong Im Woo, Noboru Yamanaka |
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| Rok vydání: | 2008 |
| Předmět: |
Eustachian tube
Clinical Sciences Microbial Sensitivity Tests Biology Inbred C57BL medicine.disease_cause Microbiology Pneumococcal Infections Bacterial cell structure lcsh:Infectious and parasitic diseases Mice chemistry.chemical_compound Streptococcus pneumoniae medicine Animals lcsh:RC109-216 Lung Pediatric Reverse Transcriptase Polymerase Chain Reaction Eustachian Tube Gene Expression Profiling Pneumonia medicine.disease Mice Inbred C57BL Otitis Media Pneumococcal infections Infectious Diseases Otitis medicine.anatomical_structure Gene Expression Regulation chemistry Medical Microbiology Pneumonia & Influenza Middle ear RNA Muramidase Disease Susceptibility Peptidoglycan medicine.symptom Lysozyme Infection Research Article |
| Zdroj: | BMC infectious diseases, vol 8, iss 1 BMC Infectious Diseases BMC Infectious Diseases, Vol 8, Iss 1, p 134 (2008) |
| ISSN: | 1471-2334 |
| DOI: | 10.1186/1471-2334-8-134 |
| Popis: | Background Lysozyme is an antimicrobial innate immune molecule degrading peptidoglycan of the bacterial cell wall. Lysozyme shows the ubiquitous expression in wide varieties of species and tissues including the tubotympanum of mammals. We aim to investigate the effects of lysozyme depletion on pneumococcal clearance from the middle ear cavity. Methods Immunohistochemistry was performed to localize lysozyme in the Eustachian tube. Lysozyme expression was compared between the wild type and the lysozyme M-/- mice using real time quantitative RT-PCR and western blotting. Muramidase activity and bactericidal activity of lysozyme was measured using a lysoplate radial diffusion assay and a liquid broth assay, respectively. To determine if depletion of lysozyme M increases a susceptibility to pneumococal otitis media, 50 CFU of S. pneumoniae 6B were transtympanically inoculated to the middle ear and viable bacteria were counted at day 3 and 7 with clinical grading of middle ear inflammation. Results Immunolabeling revealed that localization of lysozyme M and lysozyme P is specific to some/particular cell types of the Eustachian tube. Lysozyme P of lysozyme M-/- mice was mainly expressed in the submucosal gland but not in the tubal epithelium. Although lysozyme M-/- mice showed compensatory up-regulation of lysozyme P, lysozyme M depletion resulted in a decrease in both muramidase and antimicrobial activities. Deficiency in lysozyme M led to an increased susceptibility to middle ear infection with S. pneumoniae 6B and resulted in severe middle ear inflammation, compared to wild type mice. Conclusion The results suggest that lysozyme M plays an important role in protecting the middle ear from invading pathogens, particularly in the early phase. We suggest a possibility of the exogenous lysozyme as an adjuvant therapeutic agent for otitis media, but further studies are necessary. |
| Databáze: | OpenAIRE |
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