Immune complexes in Wuchereria bancrofti infection in man

The levels of immune complexes in the sera of patients with Wuchereria bancrofti infection were determined by enzyme-linked immunosorbent assay, using a rabbit antibody to the adult Setaria digitata antigens SD2-4, and by the Clq-binding assay. Approximately 3-7% of microfilaraemic subjects and 30-40% of amicrofilaraemic symptomatic patients had levels of immune complexes that were significantly higher than the levels observed in non-filarial control subjects. The antigen in the polyethylene glycol-precipitated immune complexes was isolated. This W. bancrofti antigen was found to be similar to the S. digitata antigen SD2-4. Both antigens had the properties of an acidic glycoprotein of isoelectric point around pH 3.