Surfactant protein A differentially regulates peripheral and inflammatory neutrophil chemotaxis

Am J Physiol Lung Cell Mol Physiol. 2003 Jan;284(1):L140-7. doi: 10.1152/ajplung.00125.2002. Epub 2002 Aug 30.

Abstract

Surfactant protein A (SP-A), a pulmonary lectin, plays an important role in regulating innate immune cell function. Besides accelerating pathogen clearance by pulmonary phagocytes, SP-A also stimulates alveolar macrophage chemotaxis and directed actin polymerization. We hypothesized that SP-A would also stimulate neutrophil chemotaxis. With the use of a Boyden chamber assay, we found that SP-A (0.5-25 microg/ml) did not stimulate chemotaxis of rat peripheral neutrophils or inflammatory bronchoalveolar lavage (BAL) neutrophils isolated from LPS-treated lungs. However, SP-A affected neutrophil chemotaxis toward the bacterial peptide formyl-met-leu-phe (fMLP). Surprisingly, the effect was different for the two neutrophil populations: SP-A reduced peripheral neutrophil chemotaxis toward fMLP (49 +/- 5% fMLP alone) and enhanced inflammatory BAL neutrophil chemotaxis (277 +/- 48% fMLP alone). This differential effect was not seen for the homologous proteins mannose binding lectin and complement protein 1q but was recapitulated by type IV collagen. SP-A bound both neutrophil populations comparably and did not alter formyl peptide binding. These data support a role for SP-A in regulating neutrophil migration in pulmonary tissue.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Bronchoalveolar Lavage Fluid / cytology
  • CD11b Antigen / metabolism
  • Chemotactic Factors / pharmacology
  • Chemotaxis / drug effects
  • Chemotaxis / physiology*
  • Male
  • N-Formylmethionine Leucyl-Phenylalanine / pharmacology
  • Neutrophils / drug effects
  • Neutrophils / physiology*
  • Phagocytosis / drug effects
  • Phagocytosis / physiology
  • Pneumonia / physiopathology*
  • Pulmonary Surfactant-Associated Protein A / pharmacology
  • Pulmonary Surfactant-Associated Protein A / physiology*
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, Formyl Peptide
  • Receptors, Immunologic / drug effects
  • Receptors, Immunologic / metabolism
  • Receptors, Peptide / drug effects
  • Receptors, Peptide / metabolism

Substances

  • CD11b Antigen
  • Chemotactic Factors
  • Pulmonary Surfactant-Associated Protein A
  • Receptors, Formyl Peptide
  • Receptors, Immunologic
  • Receptors, Peptide
  • N-Formylmethionine Leucyl-Phenylalanine