STUDIES OF PPLO INFECTION II. THE NEUROTOXlN OF M¥COPLASMA NEUROLYTICUM

Mycoplasma neurolyticum was identified as the cause of "rolling disease" in mice by Sabin (1) and Findlay et al. (2) in 1938. These investigators encountered the agent in the course of intracerebral passages of mouse brain homogenates in mice. The neurological syndrome was bizarre and unique, characterized by the abrupt onset of continual rolling movements to one side or the other, persisting for several hours and terminating in generalized convulsive seizures and death. Rolling was produced by intmvenons injections of broth cultures of the mycoplasma, and culture filtrates were shown to contain a thermolabile exotoxin with the same property (3). Histologic study of the brains of mice surviving for 18 hr revealed axeas of cystic degeneration in the cerebeUax poles, which were considered to be the basis for the neurologic manifestations. Recently, Tully (4) succeeded in cultivating Sabin's original strain of mycopl~sma (designated strain A) from lyophili~ed samples stored since 1943, and reexamined its properties. In confirmation of Sabin's observations, he noted that the exotoxin was readily obtained in broth filtrates of young cultures, but disappeared from cultures incubated 48 hr or longer; the washed organisms elicited the same neurologic syndrome as theexotoxin; young mice and rats were much more susceptible than mature animals; the toxicity of both exotoxin and suspensions of whole mycoplasmas was eliminated by heating at relatively low temperatures.