Enhancement of the Mouse Virulence of a Non-Vi Variant of Salmonella Typhosa by Vi Antigen

[摘要] Vi antigen was shown to be a major factor in the virulence of S. typhosa for mice. Employing the intracerebral route of infection and V and W variants of the Ty2 strain, it was observed that the Vi-containing culture was approximately 40 times more lethal than the variant devoid of this antigen.The lethality of the W form was markedly increased when it was administered simultaneously with isolated, purified Vi antigen, and this virulence enhancement was shown to be specific. Furthermore, it was demonstrated that isolated Vi antigen did not become incorporated in the bacterial cell during the infectious process, and that this substance need not be an integral part of the bacterial cell in order to contribute to virulence.Enhancement of the virulence of the W cells appeared to be due, at least in part, to the ability of Vi antigen to enhance the rate of increase in numbers of the infecting inoculum in vivo .

[学科分类] 生物科学（综合）