Characterization of biological activities of feline eosinophil granule proteins.
OBJECTIVE
To characterize eosinophil granule-derived proteins in cats.


METHODS
Eosinophils collected via peritoneal lavage from 2 cats.


METHODS
The cats were infested orally with Toxocara canis eggs and subsequently challenge-exposed with T. canis antigen injected IP to induce peritoneal eosinophilia; eosinophils were collected via peritoneal lavage. Eosinophil granule proteins were acid-extracted, separated by gel-filtration chromatography, and examined for their peroxidase, ribonuclease, and bactericidal activities; the N-terminal sequence of some of these proteins was determined and compared with homologue proteins from other species.


RESULTS
3 protein peaks were separated in the chromatogram. The first peak had both peroxidase and bactericidal activities. The second peak had ribonuclease and bactericidal activities, and the N-terminal sequence of the major protein was homologous with that of proteins of the ribonuclease A superfamily, including eosinophil ribonucleases from humans and other animal species. The third protein peak had bactericidal activity, and the N-terminal sequence of the major protein was homologous with that of human and murine major basic proteins.


CONCLUSIONS
Results indicated that feline eosinophil granules contain major basic protein and eosinophil-associated ribonuclease and the granule proteins have peroxidase, ribonuclease, and bactericidal activities. In cats, characterization of eosinophil granule proteins may be useful in elucidation of the mechanism of tissue damage in eosinophil-associated diseases and development of new treatment options for those diseases. In addition, the identification of conserved structure and function of eosinophil granule proteins in cats is relevant from an evolutionary viewpoint.
Departament de Medicina i Cirurgia Animals, Facultat de Veterinària, Universitat Autònoma de Barcelona, 08193-Bellaterra, Spain.
Alessandra
A
Fondati
Esther
E
Carreras
M Dolors
MD
Fondevila
Lluis
L
Ferrer
Claudi M
CM
Cuchillo
M Victòria
MV
Nogués
D000595:Amino Acid Sequence; D000818:Animals; D000900:Anti-Bacterial Agents / Q000378:metabolism; D000947:Antigens, Helminth / Q000276:immunology / Q000378:metabolism*; D001798:Blood Proteins / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D002415:Cats / Q000378:metabolism*; D002850:Chromatography, Gel; D047091:Eosinophil Granule Proteins; D004926:Escherichia coli; D008969:Molecular Sequence Data; D010533:Peritoneal Lavage; D010544:Peroxidases / Q000378:metabolism; D012260:Ribonucleases / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D016415:Sequence Alignment; D020539:Sequence Analysis, Protein; D017166:Toxocara canis / Q000276:immunology*
D000900:Anti-Bacterial Agents; D000947:Antigens, Helminth; D001798:Blood Proteins; D047091:Eosinophil Granule Proteins; D010544:Peroxidases; D012260:Ribonucleases