Method for concentrating antisera for preparing Mycoplasma growth inhibition discs

Mycoplasma growth inhibiting antibody in rabbit anitsera was concentrated with a dry polyacrylamide gel. Discs prepared with such concentrated antisera inhibited only the homologous organism provided the antisera had been heated at 56 degrees C for 30 min, and when dried retained their potency during storage for over two years at 4 degrees C.