ABSTRACT
Mycoplasmas can cause interstitial pneumonias inducing critical illness in humans and animals. Mycoplasma infections are characterized by an influx of neutrophils, followed by an accumulation of macrophages and lymphocytes. The present study deals with the question of which mycoplasmal components cause this host reaction. The mycoplasma-derived, macrophage-activating lipopeptide 2S-MALP-2 was used to mimic the sequelae of a mycoplasma infection. To this end, 2S-MALP-2 was intratracheally instilled into the lungs of Lewis rats, and the bronchoalveolar lavage cells were examined at different times after different doses of 2S-MALP-2. Application of 2.5 microg induced a pronounced leukocyte accumulation in the bronchoalveolar space. At 24 h after 2S-MALP-2 administration, the majority of leukocytes consisted of neutrophils, followed by macrophages, peaking on days 2 and 3. Lymphocyte numbers, although amounting to only a few percent of the total bronchoalveolar lavage cells, also increased significantly, with maximal lymphocyte accumulation occurring by 72 h after instillation. The leukocyte count of the lung interstitium was increased on day 3 after treatment. After 10 days all investigated cell populations returned to control levels. Transient chemotactic activity for neutrophils was detected in the bronchoalveolar lavage fluid early after 2S-MALP-2 application, followed by monocyte chemoattractant protein-1 activity (MCP-1) in lung homogenates. MCP-1 was produced by bronchoalveolar lavage cells upon stimulation with 2S-MALP-2. Our data indicate that mycoplasmal lipoproteins and lipopeptides are probably the most relevant mycoplasmal components for the early host reaction. The primary target cells are likely to be the alveolar macrophages liberating chemokines, which attract further leukocytes.
Subject(s)
Bacterial Proteins/immunology , Lipoproteins/immunology , Lung/immunology , Macrophage Activation/immunology , Macrophages, Alveolar/immunology , Mycoplasma fermentans/immunology , Oligopeptides/immunology , Animals , Bacterial Proteins/administration & dosage , Bacterial Proteins/chemical synthesis , Bronchoalveolar Lavage , Cell Count , Chemokine CCL2/immunology , Chemokine CCL5/administration & dosage , Chemotaxis, Leukocyte/immunology , Dose-Response Relationship, Drug , Interleukin-16/administration & dosage , Leukocytes/cytology , Leukocytes/immunology , Lipopeptides , Lipoproteins/administration & dosage , Lipoproteins/chemical synthesis , Lymphocytes/cytology , Macrophages, Alveolar/cytology , Male , Mice , Mice, Inbred C57BL , Neutrophils/immunology , Oligopeptides/administration & dosage , Oligopeptides/chemical synthesis , Rats , Rats, Inbred BN , Rats, Inbred Lew , Stereoisomerism , Time Factors , Trachea/immunologyABSTRACT
In a 73-year-old woman admitted with pulmonary embolism, a thrombus wedged across a patent foramen ovale was revealed by transesophageal echocardiography. After systemic anticoagulation, cardiac embolectomy and closure of the atrial septal defect were considered. Before surgery, repeat transesophageal echocardiography revealed only a small patent foramen ovale with no residual thrombus. We assumed dissolution of the thrombus as the patient had no sign of systemic or recurrent pulmonary embolism.