Immunoglobulin G Fc receptors of Mycoplasma synoviae.

The objective of the study was to demonstrate and characterize IgG Fc receptors of Mycoplasma synoviae. Two IgG Fc receptors were recognized with molecular weights (MW) of 80,000 and 90,000 and isoelectric focusing points (pI) of 5.3 and 4.3, respectively. The activity of the IgG Fc receptors was eliminated by exposure to 0.1 unit of protease for 10 minutes. Mild reduction in activity was observed with trypsin between 100 to 1000 units for 10 minutes. The IgG Fc receptors were resistant to exposure to 60 C for 60 minutes and to 100 C for 20 minutes. The M. synoviae IgG Fc receptors were strongly reactive to affinity-purified Fc Fragment of chicken IgG; affinity-purified chicken IgG; and serum IgG of chicken, quail, pigeon, and turkey. A moderate reaction was detected to human affinity-purified IgG, and weak reactions were detected to affinity-purified IgG of cat, cow, dog, goat, guinea pig, horse, and rabbit. No reaction occurred with IgG of duck, goose, mouse, pig or rat.