Quantitative Microassay in Cell Culture for Enterotoxin of Shigella dysenteriae 1

Abstract

Shigella dysenteriae enterotoxin is cytotoxic to HeLa-cell monolayers and results in rapid detachment of cells from glass surfaces. The number of cells that detach during incubation overnight is directly related to the quantity of toxin present in the medium. Based on these observations, a quantitative microassay, which reproducibly detected subnanogram quantities of toxin, was developed. The technique involves enumeration of the number of cells that remain fixed to glass after exposure to toxin and may also be adaptable to other cytotoxic bacterial products, such as the exotoxin of Corynebacterium diphtheriae.