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Effect of Pasteurella haemolytica outer membrane proteins on bovine neutrophils

G Iovane1, M Galdiero, M Vitiello

  • 1Dipartimento di Patologia, Facoltà di Veterinaria, Università degli Studi di Napoli Federico II, Italy.

FEMS Immunology and Medical Microbiology
|March 26, 1998
PubMed

Insights

Major outer membrane proteins from Pasteurella haemolytica affect bovine polymorphonuclear leukocytes (PMNs). These OMPs reduce PMN adherence, act as chemotaxins, and diminish phagocytic capacity and intracellular killing.

Area of Science:

  • Veterinary Immunology
  • Bacterial Pathogenesis
  • Cellular Immunology

Background:

  • Pasteurella haemolytica is a significant pathogen in bovine respiratory disease.
  • Outer membrane proteins (OMPs) are key virulence factors in Gram-negative bacteria.
  • Bovine polymorphonuclear leukocytes (PMNs) are crucial for innate immunity against bacterial infections.

Purpose of the Study:

  • To investigate the effects of Pasteurella haemolytica OMPs on the biological activity of bovine PMNs.
  • To determine the dose-dependent responses of PMNs to OMPs.
  • To assess the impact of OMPs on PMN functions such as adherence, chemotaxis, phagocytosis, and intracellular killing.

Main Methods:

  • Isolation of major outer membrane proteins (OMPs) from Pasteurella haemolytica.
  • In vitro assays to measure PMN adherence to nylon wool.
  • Chemotaxis assays to evaluate PMN migration in response to OMPs.
  • Determination of phagocytic index and intracellular killing capacity of PMNs after OMP preincubation.

Main Results:

  • OMPs induced a dose-dependent reduction in PMN adherence to nylon wool.
  • OMPs exhibited chemotactic activity for PMNs at concentrations of 5-20 microg/ml.
  • Preincubation with OMPs (5 microg/ml) significantly diminished the phagocytic index and intracellular killing capabilities of PMNs.

Conclusions:

  • Pasteurella haemolytica OMPs modulate key functions of bovine PMNs.
  • OMPs impair the ability of PMNs to combat bacterial infections, potentially contributing to disease pathogenesis.
  • These findings highlight OMPs as targets for understanding host-pathogen interactions and developing potential immunomodulatory strategies.

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