Studies on Immunity and Pathogenesis of Salmonellosis: I. Antigen—Antibody Reactions on Circulating Leucocytes of Chickens Infected with Salmonella gallinarum

A technique is described for the withdrawal of circulating leucocytes at intervals from chickens infected with Salmonella gallinarum, and for testing these cells for the presence of cytophilic antibody and bacterial polysaccharide by a cytopathic test.

The results of these experiments have shown that during the early stages of infection, circulating leucocytes develop a marked susceptibility to cytophilic antibodies in serum and later to bacterial polysaccharide. It has also been shown that humoral antibodies, demonstrable by the antiglobulin haemagglutination test, have cytophilic properties.

These results are discussed in relation to the pathogenesis of Salm. gallinarum infection in chickens, and it is suggested that during acute infection, cellular antigen—antibody reactions occur which may result in the development of a hypersensitive reaction.