First analysis of the secretome of the canine heartworm, Dirofilaria immitis.
BACKGROUND
The characterization of proteins released from filariae is an important step in addressing many of the needs in the diagnosis and treatment of these clinically important parasites, as well as contributing to a clearer understanding of their biology. This report describes findings on the proteins released during in vitro cultivation of adult Dirofilaria immitis , the causative agent of canine and feline heartworm disease. Differences in protein secretion among nematodes in vivo may relate to the ecological niche of each parasite and the pathological changes that they induce.


METHODS
The proteins in the secretions of cultured adult worms were run on Tris-Glycine gels, bands separated and peptides from each band analysed by ultra mass spectrometry and compared with a FastA dataset of predicted tryptic peptides derived from a genome sequence of D. immitis.


RESULTS
This study identified 110 proteins. Of these proteins, 52 were unique to D. immitis. A total of 23 (44%) were recognized as proteins likely to be secreted. Although these proteins were unique, the motifs were conserved compared with proteins secreted by other nematodes.


CONCLUSIONS
The present data indicate that D. immitis secretes proteins that are unique to this species, when compared with Brugia malayi. The two major functional groups of molecules represented were those representing cellular and of metabolic processes. Unique proteins might be important for maintaining an infection in the host environment, intimately involved in the pathogenesis of disease and may also provide new tools for the diagnosis of heartworm infection.
Department of Pathobiology and Diagnostic Investigation, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824, USA.
James
J
Geary
Mohamed
M
Satti
Yovany
Y
Moreno
Nicole
N
Madrill
Doug
D
Whitten
Selwyn A
SA
Headley
Dalen
D
Agnew
Timothy
T
Geary
Charles
C
Mackenzie
D020816:Amino Acid Motifs; D000818:Animals; D030562:Databases, Protein; D004183:Dirofilaria immitis / Q000378:metabolism*; D004184:Dirofilariasis / Q000469:parasitology*; D004283:Dog Diseases / Q000469:parasitology*; D004285:Dogs; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D015801:Helminth Proteins / Q000032:analysis / Q000302:isolation & purification* / Q000378:metabolism; D008297:Male; D013058:Mass Spectrometry; D058977:Molecular Sequence Annotation; D020543:Proteome; D013045:Species Specificity
D015801:Helminth Proteins; D020543:Proteome