Trypanosome-derived oligopeptidase B is released into the plasma of infected rodents, where it persists and retains full catalytic activity.
A trypsin-like serine peptidase activity, levels of which correlate with blood parasitemia levels, is present in the plasma of rats acutely infected with Trypanosoma brucei brucei. Antibodies to a trypanosome peptidase with a trypsin-like substrate specificity (oligopeptidase B [OP-Tb]) cross-reacted with a protein in the plasma of trypanosome-infected rats on a Western blot. These antibodies also abolished 80% of the activity in the plasma of trypanosome-infected rats, suggesting that the activity may be attributable to a parasite-derived peptidase. We purified the enzyme responsible for the bulk of this activity from parasite-free T. b. brucei-infected rat plasma and confirmed its identity by protein sequencing. We show that live trypanosomes do not release OP-Tb in vitro and propose that disrupted parasites release it into the host circulation, where it is unregulated and retains full catalytic activity and may thus play a role in the pathogenesis of African trypanosomiasis.
Morty
R E
RE
Department of Biochemistry, School of Molecular and Cellular Biosciences, University of Natal, Scottsville, South Africa. rory.morty@yale.edu
Lonsdale-Eccles
J D
JD
Mentele
R
R
Auerswald
E A
EA
Coetzer
T H
TH
D000818:Animals; D000913:Antibodies, Protozoan / Q000276:immunology; D015153:Blotting, Western; D002384:Catalysis; D003429:Cross Reactions; D008297:Male; D015800:Protozoan Proteins / Q000097:blood*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012697:Serine Endopeptidases / Q000097:blood* / Q000276:immunology / Q000302:isolation & purification; D014346:Trypanosoma brucei brucei / Q000201:enzymology*; D014353:Trypanosomiasis, African / Q000097:blood*
D000913:Antibodies, Protozoan; D015800:Protozoan Proteins; D012697:Serine Endopeptidases; C090703:oligopeptidase B