Detection and characterization of defective mycoplasmacidal antibody produced by rodents against Mycoplasma arthritidis.

A procedure has been developed for the detection of mycoplasmacidal antibody in the serum of rats and mice infected with Mycoplasma arthritidis. Antibody activity can apparently be measured only by using resting mycoplasma cells. The reaction is complement dependent and is usually complete within 3 h. Early antibody (5 days) could be detected only within the immunoglobulin (Ig)M fraction, whereas late antibody (42 days) is found within the IgG fraction. The mycoplasmacidal antibody was highly specific and cross reactions were not observed with other mycoplasma species. Antibody activity could be removed from serum by absorption with either viable or nonviable M. arthritidis. Cidal antibody produced by rats against other mycoplasma species was active against both resting and multiplying cells. Mycoplasmacidal antibody against M. arthritidis was detected in rats 2 days after injection of the organisms and persisted at least through 300 days. Mice usually developed antibodies by 3 days after injection of the organisms and moderate titers have been observed for as long as 487 days. Since viable mycoplasmas can persist in the peripheral circulation in the presence of antibody, it is likely that viable mycoplasma-antibody complexes are also present.