Soluble antigens and antibodies in the sera of mice infected with Trichinella spiralis, detected by a modified double counterimmunoelectrophoresis technique.

Double counterimmunoelectrophoresis, with a novel well format, was used as a sensitive technique for the rapid detection of circulating antigen and antibody in mice infected with Trichinella spiralis. In a primary infection, soluble antigen was initially detected in day 13, followed by a second wave on day 41. Circulating antibody was first apparent on day 34, increasing in intensity and number of precipitation bands until day 102. The first peak of circulating antigen is indicative of non-complexed antigen released from the developing larvae in striated muscle cells, whereas the presence of antigen late in infection is indicative of electrophoresis-labile immune complexes. On reinfection (day 35 of primary) circulating antigen was present which could be attributed to products of resident primary infection muscle larvae.