Sequential determination of circulating immune complexes in experimental filariasis.

Levels of circulating immune complexes were measured in jirds (Meriones unguiculatus) infected with the filarial nematode Brugia pahangi during an 11-month infection. Using 16 infected and 8 control animals, we found three general trends, which correspond to events in the life cycle of the filarial worm in the host, in all individually infected jirds. These were (i) an initial peak of immune complexes at 2 weeks postinfection, (ii) a drop to a minimum postinfection value near the beginning of patency, and (iii) a gradual increase in immune complex levels beginning at the time of peak adult worm size and continuing to a maximum value at approximately 10 months postinfection. Microfilarial levels and hemagglutination assay titers to adult worm antigens did not correlate with immune complex levels.