Rolling disease has been produced and studied in rats and mice, using the exotoxin of the A strain of Mycoplasma neurolyticum. The primary lesion of the brain consists of spongiform degeneration, associated with vesicle formation in the cortex and underlying white matter of the cerebral hemispheres, and in the molecular layer of the cerebellum. The brains of animals surviving 2 days or longer show extensive necrotizing lesions resembling ischemic necrosis, in both cerebral hemispheres. The brains of rats and mice with rolling disease become deeply stained by intraperitoneally injected trypan blue, indicating early disruption of the blood brain barrier. The toxin appears to be a thermolabile protein with a molecular weight exceeding 200,000. It is only active when injected by vein, and causes no disease when injected intracerebrally, intraperitoneally or subcutaneously, suggesting the existence of specific receptors within the vascular bed of the central nervous system. Protection is afforded by rabbit antibody against the toxin, but only when antibody is injected within less than 3 min after intravenous injection of toxin, indicating rapid fixation to receptors in the brain. The toxin is inactivated by incubation for 10 min at 37 degrees C with suspensions of the sedimentable component of normal brain. The inactivating factor in brain sediment is very thermostable, not affected by trypsin, and eliminated by treatment with periodate. Similar inactivation of toxin is demonstrable with water-soluble gangliosides of brain. A theoretical concept to explain the action of the toxin is proposed.

Animals↗

PubMed1966

Studies of PPLO infection. 3. Electron microscopic study of brain lesions caused by Mycoplasma neurolyticum toxin.

The ultrastructure of the experimental encephalopathy caused by Mycoplasma neurolyticum toxin has been studied. The primary changes are (a) massive distention of astrocytes by fluid, associated with degenerative changes in these cells, (b) mechanical displacement and compression of myelinated axons by swollen astrocytic processes, (c) the appearance of free, extracellular fluid in the white matter, and (d) early primary myelin degeneration without damage to axons.

Animals↗

PubMed1966

Studies of PPLO infection. IV. The neurotoxicity of intact mycoplasmas, and their production of toxin in vivo and in vitro.

Concentrated suspensions of washed Mycoplasma neurolyticum produce rolling disease in mice and rats, with neurological manifestations and pathological lesions similar to those seen with the exotoxin of this organism. Pretreatment of animals with tetracycline protects completely against the toxic effects of washed suspensions of mycoplasmas, while tetracycline affords no protection against the exotoxin. Freeze-thawing disruption of mycoplasma suspensions eliminates their neurotoxicity, while the same treatment does not affect exotoxin. The toxicity of intact organisms is not affected by exposure to the sedimentable component of brain, nor to ganglioside. These observations are interpreted to indicate that the neurotoxicity of living mycoplasmas must be due to their production of toxin after they have been injected into the animal. Resting mycoplasmas, suspended in Ringer's solution in dialysis sacs submerged in PPLO broth) produce considerable amounts of toxin within 15 min of incubation at 37 degrees C. Toxin is also produced, although in somewhat less amount, by washed organisms suspended in phosphate buffer containing glucose. The formation of toxin is prevented by the presence of puromycin, but not by the aminonucleoside analogue of puromycin, indicating that active protein synthesis is involved in the elaboration of toxin. The similarities between the neurotoxicity of the intact organisms of M. neurolyticum and Mycoplasma gallisepticum are discussed.

Animals↗

PubMed1966

The interaction of mycoplasmas with mammalian cells. I. HeLa cells, neutrophils, and eosinophils.

The ultrastructure of three mycoplasma species, Mycoplasma pneumoniae, Mycoplasma gallisepticum, and Mycoplasma neurolyticum, has been studied in isolated form as well as in HeLa cell cultures and following incubation with human peripheral blood leukocytes. During log growth phase, the organisms could be distinguished from each other on the basis of their fine structure. In mammalian cell cultures, PPLO's appeared to proliferate on the plasma membranes which had markedly increased their surface area by means of long cytoplasmic processes which extended toward and surrounded them. Some of the microorganisms affected in this way may well have lain, not in vacuoles, but at the bottom of crypts. It is suggested that the cytopathogenic effect exerted by PPLO's on some tissue cultures may be attributable to membrane damage. Mycoplasmas adhered to leukocyte plasma membranes in a similar manner. They were avidly phagocytosed by neutrophils and eosinophils with accompanying degranulation of the white cells. It is thus likely that the local inflammatory reaction induced by PPLO's does not differ in essence from that caused by bacteria.

Culture Techniques↗

PubMed1966

The interaction of mycoplasmas with mammalian cells. II. Monocytes and lymphocytes.

The incubation of mycoplasmas with human peripheral blood buffy coats resulted in the uptake of these microorganisms by more than 50% of the mononuclear cells. Mycoplasmas adhered to the plasma membranes of all leukocytes, most of which developed long cytoplasmic processes not seen in the controls. In human and rat thoracic duct lymph, about 6% of the cells ingested the microorganisms. T(2) phage and thorotrast were taken up by a similar percentage of lymphocytes. On morphological grounds, the cells which were able to take up PPLO's or particles could not be distinguished from the cells which were incapable of this function. Following phagocytosis, neither the cell nor the microorganism showed any morphological alterations over a 3 hr period of observation. The demonstration that a small percentage of "lymphocytes" are able to phagocytose may have pathological and immunological implications.

Animals↗

PubMed1966

Methaemoglobin formation by Mycoplasma gallisepticum: the role of hydrogen peroxide.

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Hydrogen Peroxide↗

PubMed1966

Studies of PPLO infection. I. The production of cerebral polyarteritis by Mycoplasma gallisepticum in turkeys; the neurotoxic property of the Mycoplasma.

Turkey poults injected intravenously with suspensions of Mycoplasma gallisepticum develop a fatal neurologic disease associated with polyarteritis affecting almost exclusively the cerebral arteries. The incubation period depends on the dose of organisms. With high doses (10(10) to 10(11) mycoplasmas) the birds become ill and die within a few hours; with lower doses (10(6) to 10(8)) neurologic manifestations appear after 7 days. The rapid onset of neurologic signs after high doses indicates the presence of a toxin in the mycoplasma, but efforts to extract toxin from disrupted organisms or to demonstrate its presence in culture fluid free of mycoplasmas have been unsuccessful. The toxin appears to be associated only with living mycoplasmas. The toxic component of M. gallisepticum is inactivated by heating the organisms at 50 degrees C, disruption by repeated cycles of freezing and thawing, and exposure to specific antibody. Treatment of turkeys with gold thiomalate furnishes partial protection against the toxic effects of large doses of mycoplasmas, and protection against the development of cerebral arteritis. Treatment with tetracycline protects completely against both toxicity and arteritis, and, when delayed, restores diseased birds to a healthy state. Cortisone, methotrexate and 6-mercaptopurine have no effect on the course or outcome of the disease. Intracerebral injections of M. gallisepticum are less toxic and lethal than when the same dose was given by vein, indicating that the organism exerts its damaging action on blood vessels by way of the blood stream. The arterial lesions resemble those of serum sickness, except for their distribution, and are associated with glomerular inflammatory lesions. However, for various reasons discussed, it is considered more likely that they result from a direct toxic action of living mycoplasmas on the vessels concerned than from an immunologic mechanism.

Animals↗