Pathogenesis of Experimental Cholera

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.

Dialysis And Ultrafiltration Of A Heat-Stable Enterotoxin From Escherichia Coli

“…The molecular size appeared to be quite different from that of cholera enterotoxin, which has been estimated to be 61,000 (Finkelstein and Lospalluto, 1969). However, the present experiments were carried out with acetoneprecipitated material, and the acetone precipitation may have affected the molecular weight of the precipitate, though the results are in general agreement with dialysis experiments which did not involve acetone precipitation (Kohler).…”

“…at 65°C. This killed any remaining organisms and destroyed heat-labile enterotoxin (Gyles and Barnum, 1969). Acetone (2040 ml) was added to the filtrate and the precipitate was allowed to settle overnight at -30°C.…”

Purification of El Tor cholera enterotoxins and comparisons with classical toxin

“…In individuals infected with I/. cholerae, CT is responsible for the drastic intestinal electrolyte secretion and fluid loss leading to the clinical state of cholera (Finkelstein & Lospalluto, 1969 ;Holmgren, 198 1 ;Finkelstein, 1984). CT is a multimeric protein with two types of subunits (Lonnroth & Holmgren, 1973;Holmgren, 1981).…”

Isolation of Vibrio cholerae in Homogenized Tissues of Liver, Gall Bladder and Bile in Rabbit Model

“…De and Dutta were the first to demonstrate this toxin (now called cholera toxin) by use of culture filtrates in rabbits [12,23]. The toxin was later purified and sequenced [14] to have a molecular mass of 84000 kDa and consists of five binding (B) subunits and one active (A) subunit [15].…”