Interaction of Staphylococcal Exfoliative Toxin with Concanavalin A

Abstract

Treatment of mouse embryo fibroblasts (MEF) grown in vitro with purified staphylococcal exfoliative toxin (ET) increased the concanavalin A (Con A) agglutinability of MEF 3.5-fold over control cells. Possible explanations for this phenomenon were investigated. ET lacked proteolytic activity on denatured casein. Con A, however, was found to interact directly with ET as evidenced by the formation of precipitation in an agar gel diffusion plate and in increased turbidity in solution. This interaction was inhibited by a-methyl-D-glucopyranoside. The ability of Con A to precipitate with ET suggests that the toxin contains a carbohydrate component and that the carbohydrate associated with ET is branched rather than linear. An analysis of a purified preparation of ET indicated the presence of 9% carbohydrate and no lipid.

Staphylococcal scalded-skin syndrome: development of a primary binding assay for human antibody to the exfoliative toxin

“…The maximum binding detected in our system was in the 30 to 40% range, whereas Brunner and Chanock (2) reported binding of 80% of their labeled mycoplasma antigen. Previously we reported the possibility of the ET being a glycoprotein (18). A possible explanation for the lower binding figures we obtained may be as-cribable to the glycoprotein nature of our antigen.…”

“…Crude toxin was precipitated from the HIB cultures by addition of aqueous saturated (NH4)2SO4 to a final concentration of 80%. The crude toxin was collected by centrifugation after standing at 4 C for 18 h, dissolved in distilled water, and dialyzed against 0.0015 M phosphate buffer, pH 7.3, to free it of (NH4)2S04. After lyophilization, the crude toxin was electrofocused in a glycerol density gradient with 1% carrier ampholytes (LKB Instruments Inc.), pH 6 to 8, and the fractions between pH 6 and 7 were collected and pooled.…”

Nonenteric toxins of Staphylococcus aureus.

“…Certain isolation procedures could cause the toxin to complex with other components that would make the toxin appear to have a higher molecular weight. For example, purified preparations of ET, isolated in our laboratory by isoelectric density gradient electrophoresis, were glycoproteins containing 9% carbohydrate (147). B. Wiley (unpublished results) showed that the carbohydrate was not a contaminant from the glycerol density gradient used for electrofocusing.…”

Clinical, Microbial, and Biochemical Aspects of the Exfoliative Toxins Causing Staphylococcal Scalded-Skin Syndrome

“…Native ET was also shown to have no intrinsic arylsulfatase, ␤-galactosidase, or cathepsin activity (these enzymes are normally present in lysosomes) (278). The toxins did not have any enzymatic activity toward known nonspecific substrates, including casein (134,218), and using sensitivity plates (15,21), and their activity was unaffected by any of a wide range of metabolic inhibitors tested (24,249). Even attempts at crystallizing either ETA (289) or ETB (180) to determine their three-dimensional structure, which might shed light on their mechanism of action, met with little success because of difficulty in obtaining stable crystals.…”