Variations in complement activation of brugia patei brugia malayi and brugia pahangi microfilariae
Rao, U.R.; Vickery, A.C.; Nayar, J.K.; Kwa, B.H.
Kaohsiung Journal of Medical Sciences 7(4): 160-167
The complement of fresh normal heterozygotic BALB/C (nu/+) and nude (nu/nu) mice was activated by sheathed microfilariae (Mf) of Brugia malayi and B. pahangi but not by B. patei. Mouse C3 was detected by immunofluorescence on the sheathed surface of B. malayi and B. pahangi Mf but not on B. patei Mf. The bound complement promoted macrophage and neutrophil mediated adherence and cytotoxicity to these Mf. However, BALB/C nu/+ or nu/nu mouse macrophages and neutrophils adhered to exsheathed Mf of B. patei and killed them in the presence of fresh normal mouse serum (NMS). C3 molecules were detected on the cuticle of exsheathed Mf of B. patei and B. malayi. Fresh NMS (nu/t or nu/nu) depleted of complement factors by heating or by zymosan or anti-mouse C3, failed to promote cell adherence to these parasites. EDTA but not EGTA abolished the adherence activity to sheathed and exsheathed Mf of B. malayi, whereas both EGTA and EDTA abolished the adherence activity to exsheathed Mf of B. patei and sheathed Mf of B. pahangi suggesting the different pathways of complement activation by these closely related species. Macrophages and neutrophils from peritoneal exudate cells of nu/+ or nu/nu were equally potent in adherence and killing of Mf Transfused B. patei but not B. malayi or B. pahangi Mf were recovered from the peritoneal cavity of BALB/C mice with no cell adherence and cytoxicity.