A solid-phase enzyme immunoassay using guinea pig C3 to detect anti-Mycoplasma pulmonis antibody in the sera of infected rats.

Abstract

A solid-phase enzyme immunoassay to detect antibodies by the measurement of guinea pig C3 bound to antigen-antibody complex has been developed. Briefly, antibodies in heat-inactivated sera are reacted with antigens coated on the surface of microtiter plates. Guinea pig C3 is bound to the antigen-antibody complexes, and then the amount of C3 is measured using horseradish peroxidase-labeled anti-C3.When this enzyme immunoassay was applied to the diagnosis of Mycoplasma pulmonis infection in rats, high sensitivity and specificity were observed : 95% or more of 20 sera from M. pulmonis-infected rats confirmed by cultivation were positive regardless of the antigen strains used, while no positive reaction was detected in 20 normal rat sera. In the complement fixation test, only 12 were positive out of the above-mentioned 20 positive sera, despite the use of the solid-phase antigen which gave the maximal binding.The present assay is simple, highly sensitive and specific, and is considered to be a useful tool for the diagnosis of M. pulmonis infection in rats.