Measurement of antigen-antibody complexes in mouse sera by conglutinin, C1q and rheumatoid factor solid phase binding assays.

The application of three solid phase tests for the detection of antigen-antibody complexes in the sera of inbred and selectively-bred mice with experimentally induced chronic antigen-antibody complex disease is described. Two of the tests used--the C1q binding assay (C1qBA) and the conglutinin binding assay (KBA)--were previously described methods which we have modified for the detection of murine complexes. The third test is a new solid phase polyclonal rheumatoid factor binding assay (RFBA). The results demonstrate that the correlation of positivity with the three methods varied during the course of a chronic disease but in general results with the KBA showed a better correlation with the RFBA than with the C1qBA. Furthermore, the KBA and RFBA preferentially bound complexes of lower molecular weight than did the C1qBA. It is suggested that the parallel use of these three tests during the study of murine antigen-antibody complex disease will provide valuable information concerning the nature of the complexes involved; since the three tests, when run in parallel, will detect large complement fixing complexes (C1q), small complement fixing complexes (KBA) and small non-complement fixing complexes (RFBA).