Abstract
An experiment was carried out to clarify the rise and fall of soluble circulating antigen (SCA) in relation to the fluctuation of antibody levels in dogs experimentally infected with Dirofilaria immitis. For detection of SCA, counterimmunoelectrophoresis (CIEP) was performed continually in these dogs at given intervals. Besides CIEP, the double diffusion technique (DD) was used for examining the antibody level. When CIEP was conduced on the serum of dogs experimentally infected with D. immitis, SCA was first detected as early as 1 month after infection, and either SCA or antibody in the blood showed a rise and fall with the lapse of time, but antigen and/or antibody were always detectable in the course of infection. On the other hand, antibody appeared inconstantly in each infected dog in the course of infection when examined by DD. The results indicated that a high level of SCA was present in the circulating blood of dogs infected with D. immitis. As a result, CIEP was regarded as a highly reliable and useful diagnostic tool for examining infection with D. immitis, since it could detect both SCA and antibody simultaneously and the procedure was completed in a shorter time than DD or immunoelectrophoresis.
