muramidase and Pneumonia--Viral

The current state of knowledge of lung defenses has been reviewed. First, mechanical factors such as aerodynamic filtration and mucociliary transport were considered. Then, in general terms, the contributions of alveolar macrophages, neutrophils, lymphocytes, and immunoglobulins, and the roles of complement, antiproteases, lysozyme, and fibronectin were examined. Interactions between these components may regulate their effect. Finally, the responses to five specific microorganisms were reviewed to illustrate different aspects of the lung's defenses. Streptococcus pneumoniae was selected as a representative extracellular bacterial pathogen, Mycobacterium tuberculosis as an intracellular bacterial pathogen, Mycoplasma pneumoniae because it elicits significant humoral and cell-mediated immunity, respiratory syncytial virus as an example of a local viral pathogen, and measles as a viral pathogen that causes generalized disease. It was shown that these responses may not always be beneficial for the host. For each of the five infections, recommendations for improving the outcome were made.

Topics: Cilia; Complement System Proteins; Fibronectins; Filtration; Humans; Immunoglobulins; Lung; Lymphocytes; Macrophages; Measles; Mucus; Muramidase; Neutrophils; Phagocytosis; Pneumonia, Mycoplasma; Pneumonia, Pneumococcal; Pneumonia, Viral; Protease Inhibitors; Respiratory Tract Infections; Respirovirus Infections; Tuberculosis, Pulmonary

Severe pneumonia is found in simultaneous influenza pneumonia and bacterial infection, and suggests a relationship with immunological mechanisms. Here, we performed two-dimensional gel electrophoresis to detect immunological molecules related to the fulminant pneumonia caused by influenza virus and Streptococcus pneumoniae co-infection in mice. We found two spots that were expressed strongly in co-infected mouse lungs, compared with S. pneumoniae or influenza virus singly infected mouse lungs. The spots were analysed by mass spectrometry, and identified as alpha-1 anti-trypsin (A1AT), known as an anti-protease for neutrophil-derived proteolytic enzymes, and creatine kinase, which reflects a greater degree of lung damage and cell death. A1AT expression was increased significantly, and proteolytic enzymes from neutrophils, such as neutrophil elastase, myeloperoxidase and lysozyme, were also secreted abundantly in influenza virus and S. pneumoniae co-infected lungs compared with S. pneumoniae or influenza virus singly infected lungs. These data suggest that A1AT may play a central role as a molecule with broad anti-inflammatory properties, and regulation of the neutrophil-mediated severe lung inflammation is important in the pathogenesis of co-infection with influenza virus and bacteria.

Topics: alpha 1-Antitrypsin; Animals; Bronchoalveolar Lavage Fluid; Chemokine CXCL2; Creatine Kinase; Disease Susceptibility; Electrophoresis, Gel, Two-Dimensional; Influenza A virus; Leukocyte Elastase; Lung; Male; Mice; Mice, Inbred CBA; Muramidase; Orthomyxoviridae Infections; Peroxidase; Pneumonia, Pneumococcal; Pneumonia, Viral

A total of 359 patients with acute pneumonia and 152 practically healthy subjects comprising the control group were examined. Immunofluorescence was used to investigate nasopharyngeal washings for detecting antigens of influenza and parainfluenza viruses, respiratory-syncytial virus, adenoviruses, whereas serological studies according to the hemagglutination delay test with diagnostic agents for detecting influenza A1, A2, B, types 1, 2 and 3 parainfluenza, and the complement fixation test were made to detect antibodies against adenoviruses. Serological (65%) and immunofluorescence (63%) studies revealed associations of different viruses: type 3 and 1 parainfluenza, respiratory-syncytial virus (73%) with adenoviruses, influenza B, A2, type 2 parainfluenza. Association of different bacteria was observed in 67% of patients: hemolytic staphylococcus (65%), hemolytic streptococcus (50%), pneumococci (45%), P. aeruginosa (40%), P. mirabilis (35%), E. coli (30%), enterococci (25%). Associations of 3-2 causative agents were predominant (53%). Marked decrease in the content of complement and beta-lysins, elevation of the level of lysozyme were observed in patients with viral-bacterial and viral pneumonias as compared to the same characteristics in patients with bacterial pneumonia and in control group subjects.

Topics: Acute Disease; Adolescent; Adult; Aged; Antibodies, Bacterial; Antibodies, Viral; Antimicrobial Cationic Peptides; Blood Proteins; Complement System Proteins; Humans; Immunity, Innate; Middle Aged; Muramidase; Pneumonia; Pneumonia, Viral; Proteins