L-selectin is required for fMLP- but not C5a-induced margination of neutrophils in pulmonary circulation

Abstract

. L-selectin is required for fMLP-but not C5a-induced margination of neutrophils in pulmonary circulation. Am J Physiol Regulatory Integrative Comp Physiol 282: R1245-R1252, 2002. First published December 21, 2001 10.1152/ajpregu.00540. 2001.-To study the role of L-selectin in neutrophil (PMN) margination and sequestration in the pulmonary microcirculation, maximally active concentrations of C5a (900 pmol/g) and N-formylmethionyl-leucyl-phenylalanine (fMLP; 0.34 pmol/g) were injected into the jugular vein of wild-type or L-selectin-deficient C57BL/6 mice. In wild-type mice administered C5a or fMLP, 92 Ϯ 1% and 34 Ϯ 9%, respectively, of peripheral blood PMN were trapped mostly in the pulmonary circulation as determined by immunohistochemistry and myeloperoxidase activity. In wild-type mice treated with F(abЈ) 2 fragments of the L-selectin monoclonal antibody MEL-14 or in L-selectin-deficient mice, C5a-induced neutropenia was not significantly reduced, but the decrease in peripheral PMN in response to fMLP was completely abolished, indicating that L-selectin is necessary for fMLP-but not C5a-induced pulmonary margination. Immunostained lung sections of fMLP-or C5a-treated mice showed sequestered neutrophils in alveolar capillaries with no evidence of neutrophil aggregates. We conclude that chemoattractant-induced PMN margination in the pulmonary circulation can occur by two separate mechanisms, one of which requires L-selectin.

Adenosine receptor A2b on hematopoietic cells mediates LPS-induced migration of PMNs into the lung interstitium

“…Pulmonary circulation was perfused free of blood, the trachea was cannulated, and the lung was inflated by 4% paraformaldehyde (PFA) for 10 min at 25 cmH 2O. The lungs were removed and fixed in PFA for 24 h. Using the avidin-biotin technique (Vektor Laboratories, Burlingame, CA), paraffin-embedded sections (5 m) were stained for PMNs, as described previously (32). Briefly, lung sections were deparaffinized and rehydrated, and nonspecific binding was blocked by incubation with avidin, 10% rabbit serum, and 0.5% fish skin gelatin oil.…”

Critical role of endothelial CXCR2 in LPS-induced neutrophil migration into the lung

“…The lungs were subsequently removed and fixed in PFA for 24 hours. Paraffin-embedded sections (5 µm) were stained for CXCR2 using the avidin-biotin technique (Vector Laboratories) as previously described (45). Briefly, deparaffinized and rehydrated sections were incubated with avidin, 10% rabbit serum, and 0.5% fish skin gelatin oil for 1 hour to block nonspecific binding.…”

Adenosine Receptor A1 Regulates Polymorphonuclear Cell Trafficking and Microvascular Permeability in Lipopolysaccharide-Induced Lung Injury

“…The pulmonary circulation was perfused free of blood, the trachea was cannulated, and the lung was inflated with 4% paraformaldehyde (PFA) for 10 min at 25 cm H 2 O. The lungs were subsequently removed and fixed in PFA for 24 h. Paraffin-embedded sections (5 mm) were stained for PMNs utilizing the avidin-biotin technique (Vector Laboratories, Burlingame, CA) as previously described (35). Briefly, deparaffinized and rehydrated sections were incubated with avidin, 10% rabbit serum, and 0.5% fish skin gelatin oil for 1 h to block nonspecific binding.…”