The alternative pathway of complement in sheep during the course of infection with Trypanosoma congolense and after Berenil treatment.
Experimental T. congolense infections in sheep resulted in a striking decrease in parameters of the alternative complement pathway (ACP), ie. factor B, C3 and haemolytic complement activity (HA) initiated via the ACP. The levels of factor B, C3 and HA declined before, during and after the first wave of parasitemia which reached a peak at day 8. Levels of 20 to 25% of normal values (factor B) and 20% (C3, HA) persisted throughout the course of the infection. After Berenil treatment, when no parasites were detected in blood, their serum levels remained low. The returned to normal values about 8 (factor B) to 20 days (C3, HA) after trypanocidal treatment. Serum concentrations of factor B were significantly elevated in some, but not all sheep 6 days after infection with T. congolense. The sheep were tested for their potential state of immuno-modulation by immunization with Brucella abortus 4 days after trypanocidal treatment. In contrast to other sheep, the sheep which had shown early elevated serum factor B levels were found to express immune enhancement. It is suggested that there might be a positive correlation between the degree of enhanced serum levels of factor B at the early stage of infection and enhanced immune responsiveness.
D000818:Animals; D000907:Antibodies, Bacterial / Q000096:biosynthesis; D002003:Brucella abortus / Q000276:immunology; D003167:Complement Activation; D003176:Complement C3 / Q000032:analysis; D011415:Complement Factor B / Q000032:analysis; D003170:Complement Pathway, Alternative; D004133:Diminazene / Q000031:analogs & derivatives / Q000627:therapeutic use; D012756:Sheep; D012757:Sheep Diseases / Q000276:immunology*; D014348:Trypanosoma congolense / Q000276:immunology; D014353:Trypanosomiasis, African / Q000188:drug therapy / Q000276:immunology*
D000907:Antibodies, Bacterial; D003176:Complement C3; D011415:Complement Factor B; C003915:diminazene aceturate; D004133:Diminazene