American journal of veterinary research
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Sera from Trichinella spiralis digestion-negative swine contained variable amounts of two immunoglobins that reacted with T spiralis antigen in the indirect enzyme-labeled antibody test for trichinosis. One of these immunoglobins, detected by heavy chain-specific anti-swine immunoglobulin G (IgG) conjugate, was removed by absorption with T spiralis larvae. A second immunoglobin, detected by heavy chain-specific anti-swine IgM, was not removed by absorption with T spiralis larvae and increased in amount with the age of the animal. ⋯ In contrast to IgG anti-T spiralis antibody from experimentally infected animals, neither of these immunoglobins could be detected in double-diffusion tests against the antigen or by counter immunoelectrophoresis. Either of these immunoglobins could interfere with the indirect test for T spiralis antibodies, depending upon whether anti-swine IgG or IgM conjugate is used. The factors which initiate synthesis and control serum concentrations of these immunoglobins are not known.