Chronic arthritis of rabbits induced by mycoplasmas. IV. Protective effect of immunization and prior infection.

Rabbits exposed to Mycoplasma arthritidis either by active immunization with killed mycoplasmas or by primary infection in the right knee were protected against intra-articular challenge with viable M. arthritidis in the left knee. This protection extended to the challenged knees of preinfected rabbits even while highly active inflammation persisted in the initially injected joints. We propose that the protection is mediated by antibody, probably metabolic-inhibiting antibody, present in the joint at the time of challenge.