SEROLOGICAL STUDY OF THE MUCINASES FROM SHIGELLA FLEXNERI

Abstract

splitting enzyme in cultures of Vibrio comma which causes desquamation of the intestinal mucosa of guinea pigs and have suggested a role for this mucinase in the pathogenesis of Asiatic cholera. While possession of this enzyme may be an important factor in determining the virulence of cholera strains, it is by no means the only attribute, since avirulent vibrio cultures also elaborate it (Singh and Ahuja, 1953; Freter, 1955). Nevertheless the addition of this material to cholera vaccine is being considered (Lowenthal, 1956), and studies have indicated that at least two distinct serological types of the enzyme designated types A and B, are elaborated by cholera cultures (Freter, 1955). In view of the similarity of some of the clinical manifestations of cholera and bacillary dysentery, cultures representing the various serotypes of Shigella were screened for mucinolytic activity. It was found that of the strains tested only those of Shigella flexneri strains 2a, X, and Y produced demonstrable amounts of mucinase (Formal and Lowenthal, 1956). This communication presents the results of a serological study of the Shigella mucinases and in addition describes a mucinase from a culture of Escherichia coli. MIATERIALS AND METHODS Cultures. Some of the strains used in this study came from the culture collection of the Walter Reed Army Institute of Research and others from cases of diarrhea in Japan and Mexico City. Mucinase preparations. The mucinase prep-arations for serological tests consisted of crude culture supernatants obtained by the method previously described (Formal and Lowenthal, 1956). For antiserum production, rabbits were immunized with concentrated enzyme prepara-tions. In the case of the flexner and coli muci-nases, the concentration was accomplished either by lyophilization or by precipitation at 4 C with 60 per cent (by volume) acetone of the crude supernatant and resuspending the resulting solid material in one tenth its original volume. The cholera mucinases were concentrated using am-monium sulfate precipitation as described b