| First Author | Burns AR | Year | 1994 |
| Journal | J Immunol | Volume | 153 |
| Issue | 7 | Pages | 3189-98 |
| PubMed ID | 7916369 | Mgi Jnum | J:20419 |
| Mgi Id | MGI:68511 | Doi | 10.4049/jimmunol.153.7.3189 |
| Citation | Burns AR, et al. (1994) Quantitation of ICAM-1 expression in mouse lung during pneumonia. J Immunol 153(7):3189-98 |
| abstractText | In the systemic circulation, neutrophil emigration into sites of acute inflammation is mediated through the leukocyte adhesion complex, CD11/CD18. ICAM-1 is an inducible endothelial ligand for CD11a/CD18 and CD11b/CD18. Streptococcus pneumoniae elicits neutrophil emigration through a CD18-independent mechanism whereas Escherichia coli endotoxin elicits emigration through a CD18-dependent mechanism in rabbit lungs. To determine whether ICAM-1 is up-modulated in the lung during CD18-independent and CD18-dependent emigration, ultrastructural immunogold-labeling studies were performed on BALB/c mice given airway instillates of S. pneumoniae or E. coli endotoxin. Ultrathin cryosections of frozen lung tissue were immunogold labeled with the mAb YN1/1.7.4 against the murine homologue of human ICAM-1. Gold particles on the plasma membranes of alveolar endothelial and epithelial cells were quantitated by transmission electron microscopy. Capillary endothelial ICAM-1 expression did not change during neutrophil emigration toward S. pneumoniae, a CD18-independent pathway in rabbits. In contrast, ICAM-1 expression increased 4.2-fold in response to E. coli endotoxin (known to elicit CD18-dependent emigration in mice), suggesting that the mechanism of adhesion may be regulated by the expression of endothelial rather than neutrophil adhesion molecules. Constitutive expression of ICAM-1 on alveolar epithelial cells was 22-fold greater than on capillary endothelium. Epithelial expression was mainly restricted to type I pneumocytes, whereas type II pneumocytes, the precursors of type I cells, expressed little or no ICAM-1. However, during pneumonia, type II but not type I pneumocytes showed increased ICAM-1 expression, suggesting that ICAM-1 expression represents an early differentiation even in response to epithelial injury. |
