No abstract

No abstract

Choleragen, a diarrheagenic protein enterotoxin elaborated by Vibrio cholerae, has been isolated from the supernate of fermenter cultures by steps involving ammonium sulfate precipitation, DEAE cellulose, Sephadex G-75, and Agarose A-5m chromatography. The resulting product appears to be pure according to immunoelectrophoretic, disc electrophoretic, ultracentrifugal, and immunologic criteria. Sephadex gel filtration and membrane filtration studies suggest a molecular size of 61,000. The isolated product is highly active in inducing experimental cholera in infant and adult rabbit models. It also elicits, in small dosage, an increased vascular permeability in skin. These observations indicate that choleragenicity and increased vascular permeability are intimately associated phenomena and may be manifestations of the same basic mechanism. An additional, antigenically identical, protein has also been isolated by the same procedures. The latter substance, termed "choleragenoid", lacks the permeability effect and choleragenicity of the choleragen moiety. Its size (estimated from Sephadex gel filtration at 42,000) is smaller than that of choleragen and it also differs in charge. Choleragenoid may prove useful as a nontoxic immunogen to protect against pathologic effects of V. cholerae infection.

No abstract

No abstract

The exo-enterotoxin of Vibrio cholerae has been obtained in crystalline form. A solution of the crystalline protein was equal in potency to the parent pure toxin in both choleragenicity and skin reactivity. Crystals of the natural toxoid, choleragenoid, resemble those of the toxin in appearance. A solution of crystalline choleragenoid was equivalent to the parent preparation in the flocculation test.

The relatively simple composition of hyaline cartilage (1, 2) offers a unique opportunity to investigate the mechanism of erosion of this tissue in the presence of inflammatory synovitis. Shatton, Schubert and Malawista (1,2) have shown that about half of the dry weight of bovine nasal cartilage consists of chondromucoprotein material. A protein preparation of similar composition has been isolated from human rib cartilage (3). The other half of dried cartilage consists mainly of collagen (2). In the absence of evidence of an enzyme that can attack native collagen at physiological pH, it appeared logical to investigate the possibility that the primary process occurring during the erosion of cartilage was the degradation of the chondromucoprotein. Accordingly, the effect of extracts of leukocytes and inflamed synovial membrane on the chondromucoprotein was studied.Chondromucoprotein as extracted by Shatton and Schubert (1) contains about 70 per cent chondroitin sulfate and 30 per cent protein. It is water-soluble and highly viscous in solution. The latter property is in contrast to that of free chondroitin sulfate, which forms solutions of relatively low viscosity. On the basis of this difference, the rate of breakdown of the mucoprotein under the influence of cell-free extracts of leukocytes from the peripheral blood and of synovial membranes from patients with a variety of arthritides has been measured. Rapid decrease in viscosity on treatment with extracts of normal leukocytes and rheumatoid synovial membranes has been observed. Leukocyte extracts. Pellets of leukocytes obtained from the peripheral blood of normal subjects and of hospitalized patients with a normal peripheral blood picture were prepared by the addition of 1 vol of 6 per cent dextran solution to 3 vol of heparinized blood distributed in 15 ml conical centrifuge tubes. After allowing them to stand for 1 hour at 370 C, the supernatants were removed and centrifuged. The pellet obtained from 60 ml of heparinized blood was taken up in 2 ml of distilled water and alternately frozen and thawed 10 times using an ice-salt bath. The mixture was then ground in a small glass homogenizer and centrifuged. The clear pink supernatant was brought to a volume of 3 ml.Synovial membrane extracts. Synovial membrane was obtained through the cooperation of Dr. R. L. Preston from patients with rheumatoid arthritis, ankylosing spondylitis, and osteoarthritis of the hip and knee, who were undergoing joint surgery. The fresh synovial tissue was minced with scissors in the cold. Approximately 2.5 g of minced tissue was homogenized in 2.5 ml of water using a glass homogenizer. The homogenate was then alternately frozen and thawed 10 times using an ice-salt mixture and cleared by centrifugation.Viscosity measurements. Four ml of a 0.5 per cent solution of the chondromucoprotein in neutral salinephosphate buffer (0.075 M sodium chloride and 0.075 M phosphate) was pipetted into a 4 ml Ostwald viscosimeter placed in a water bath at 37°C. Following a period of 15 minutes for tem...

Since the discovery that sera from patients with rheumatoid arthritis have the capacity to agglutinate sensitized sheep erythrocytes (1), much attention has been directed to the constituents in serum responsible for this phenomenon. This has resulted not only in the development of a number of diagnostic tests, but also in considerable investigation (2) into the nature of the responsible serum constituent. The latter has been referred to as the rheumatoid factor (3).Ziff and coworkers (4) demonstrated that the agglutinating activity of rheumatoid serum is precipitated in the euglobulin fraction, and Svartz and Schlossmann (5) showed that it precipitated in the "cold globulin" fraction. On zone electrophoresis of the cold globulin precipitate, agglutinating activity was found in the gamma globulin. This has also been demonstrated by paper electrophoresis of precipitated material obtained after dilution of rheumatoid serum with water (6). Ultracentrifugal studies of rheumatoid sera and euglobulin fractions have shown that the factor circulates as a high molecular weight component with a sedimentation coefficient of 22 S (7), and that there is a correlation between the quantity of the 22 S component found and the agglutination titer.With the development of a suitable chromatographic system for the fractionation of serum proteins, it has been possible to apply the chromatographic method to the investigation of the rheumatoid factor. The cellulose ion exchangers described by Sober and Peterson (8,9) have therefore been employed by , and by Svartz et al. (13), for the fractionation of rheumatoid serum and euglobnlin fractions. The present paper describes the isolation of rheumatoid factor using an anion exchanger and further fractionation of the purified material on a cation exchanger.