Delayed hypersensitivity skin test for detection of immune responses against Salmonella in cattle.

Intracutaneous injection of a crude supernatant fraction from homogenised Salmonella typhimurium (O antigens 4, 5, 12) or S dublin (O antigens 9, 12) in 250 cattle or calves from salmonella infected herds elicited in 27 per cent and 42 per cent, respectively, a local dermal reaction. Both the time course and histological examinations of biopsy materials indicated a delayed type of hypersensitivity reaction. No local dermal reactions were seen in any of 250 heads of cattle or calves from control herds. The immunological characterisation of the S typhimurium and S dublin crude extracts revealed that they contained O antigens (ie, lipopolysaccharides) and outer membrane proteins, porins. A Yersinia enterocolitica serotype O3 extract did not evoke skin reactions in any of 70 tested animals. Fifteen calves infected with S typhimurium and five with S dublin exhibited increased ELISA titres against the O antigenically homologous lipopolysaccharides.