Inhibition by Normal Rabbit Sera of the Growth of t-mycoplasma Strains Isolated from Different Animal Species

SUMMARY: Normal rabbit sera contain a factor that, in conjunction with a heat labile component of guinea-pig or foetal calf serum, prevented the growth of human and other t-mycoplasmas but had little or no effect on bovine t-mycoplasmas examined. Susceptibility of human strains to the action of this substance was altered by growth in different media. The possibility that the factor might be antibody is discussed.