[Partial purification and properties of a mitogenic factor from Mycoplasma arthritidis].

M. arthritidis PG6 in a dose of 10(7) colony-forming units per ml was shown to produce a highly pronounced mitogenic effect, linked with a thermolabile factor, on the splenocytes of mice and rats. The mitogenic factor was absent in the lipid fraction and in the fraction formed by easily extractable mycoplasmal proteins. The supernatant fluid obtained after the sedimentation of M. arthritidis globular proteins with ammonium sulfate stimulated lymphocytes as actively as the intact culture of M. arthritidis. The fractionation of the supernatant fluid in columns packed with Sephadex G-200 revealed that the greatest mitogenic effect was produced by the fraction with a molecular weight of 240,000 daltons. It seems that the arthritogenic properties of M. arthritidis are linked precisely with this subcomponent.