Antigen-specific circulating immune complexes in Coxiella burnetii-infected guinea pigs.

An antigen-specific conglutinin-binding assay was developed with artificial immune complexes of Coxiella burnetii and an enzyme-linked immunosorbent assay for the detection of circulating immune complexes. Sera from guinea pigs infected with C. burnetii were examined by this assay, and the percentages of infected guinea pigs with C. burnetii antigen-specific circulating immune complexes were 71, 93, 74, 65, 49, and 27%, respectively, from the first to sixth week after infection. C. burnetii antigen eluted from circulating immune complexes by acid dissociation was detected by counterimmunoelectrophoresis. The antigen-specific conglutinin binding assay was specific, sensitive, and reproducible for assay of circulating immune complexes.