Immunity to salmonella infection in mice

Abstract

Experiments on immunity produced by vaccine were carried out in mice with two strains of salmonella.Against intraperitoneal challenge protection was such that 40–80 % of vaccinated mice survived a dose that killed almost all controls. This level of immunity appeared to be maintained with little change for at least 5–7 months. An explanation for this stability is suggested.Against infection by the natural route, either by direct feeding or by exposure to infected animals, protection from vaccine was of a comparatively low order.Resistance to infection by an artificial route was, therefore, not a measure of resistance to infection by the natural route.