Serum dependent cell‐mediated immune reactions to Brugia pahangi infective larvae*

Abstract

Fresh normal rat serum (fNRS) promoted adherence and cytotoxicity of albino rat neutrophils and macrophages to Brugia pahangi infective larvae (L3) in vitro. EDTA and not EGTA abolished the adherence activity suggesting the involvement of complement components via the alternate pathway. C3 molecules were detected on the surface of the parasite by immunofluorescence. fNRS depleted of complement by treatment with Zymosan A or of factor B by heating at 50 degrees C for 20 min, failed to promote cell adherence to the parasite. fNRS and cells from albino rat were more potent in inducing cytotoxicity to L3 than those from jird or Mastomys which may reflect the greater resistance offered by the albino rat to B. pahangi infection. In the presence of IgG and a heat labile factor, possibly complement, of immune serum, neutrophils and macrophages and to a lesser extent eosinophils adhered to and killed the larvae. Immune sera raised against microfilariae of different filarial parasites promoted cell-mediated cytotoxicity to B. pahangi L3 suggesting sharing of antigens between the two stages.

Immunization with Wuchereria bancrofti Glutathione-S-transferase Elicits a Mixed Th1/Th2 Type of Protective Immune Response Against Filarial Infection in Mastomys

“…ADCC is one of the principal immunological mechanisms working behind the dis-appearance of circulating filarial parasites and their clearance [15,16,23]. Here in, we observed that the sera from mastomys immunized with rWbGST promoted adherence of peritoneal exudate cells to L 3 larvae and induced significant killing of parasite (71.55 % of cytotoxicity against L3).…”

“…The cytotoxic effect of anti-rWbGST antibodies against B. malayi L 3 larvae was determined by in vitro cytotoxicity assay by the method described previously [7,15,16]. Pooled sera samples from immunized mastomys before and after depletion of anti-WbGST antibodies were used in this assay.…”

Critical Role for IgM in Host Protection in Experimental Filarial Infection

“…We reasoned that the defect in these mice, in contrast to T cell-deficient mice, was not in cell recruitment but at a later stage in host defense, perhaps in adherence of leukocytes to larvae to initiate granuloma formation. To determine whether IgM played a role in adherence of PECs to worms, we used an adaptation of an in vitro assay previously described by Chandrashekar et al (23). We tested the adherence of peritoneal cells to Brugia L3 from naive or primed wt and secIgM Ϫ/Ϫ mice in the presence of either naive or primed sera.…”

Role of recombinant SXP/RAL-2 family protein Wuchereria bancrofti L2 (rWbL2) as vaccine candidate in lymphatic filariasis in mastomys

“…22,23 ADCC is one of the principal immunological mechanisms working behind the dis-appearance of circulating filarial parasites and their clearance. 15,16,24 Here in, we observed that the sera from mastomys immunized with rWbL 2 promoted adherence of peritoneal exudate cells to L 3 larvae and induced significant killing of parasite (53.89% of cytotoxicity against L 3 ). Whereas, depletion of these antibodies from the sera of immunized mastomys reverted the killing activity of parasite.…”

“…7,15,16 Pooled sera samples from immunized mastomys before and after depletion of anti-WbL 2 antibodies were used in this assay. The ADCC assay was performed by adding about 20 L 3 larvae of B. malayi to a suspension of peritoneal exudates cells (PEC; 2 x 10 5 cells / well in 100 μl of RPMI medium) collected from normal mastomys.…”