Immunological study of typhoid fever in man. II Cell-mediated immune response.

The development of cell-mediated immune response to lipopolysaccharide and Barber protein from Salmonella typhi was investigated in patients suffering from typhoid fever. The cell-mediated immunity as measured by the leukocyte adherence inhibition test, was demonstrable in 77% of patients with typhoid fever but only in 5.6% of healthy controls. It was found that cell-mediated immune response appeared after the first week of illness and persisted for at least 4 weeks. The time course development of cell-mediated immune response and humoral immune response was correlated but the magnitude of each response was independent on one another.

Detection of Salmonella C1, D and V1 antigens, by coagglutination, in blood cultures from patients with Salmonella infections.

Protein A-containing Staphylococcus aureus was coupled to Salmonella C1, D and Vi monovalent antisera to produce C1-, D- and Vi-COAG reagents. The reagents were used to detect their homologous Salmonella antigens in blood cultures (BC). The D and Vi antigens were detected in 79 of 239 BC from patients with suspected typhoid fever and Salmonella typhi was later isolated from the same 79 BC. The C1 antigen was detected in 8 BC from which only S. oranienburg was later isolated. The COAG test was generally positive at the same time the BC became culture positive. However, because of subculture and biochemical identification requirements the COAG test could be interpreted 1-2 days before culture results were available. The COAG test can be used to presumptively identify Salmonella typhi and Salmonella group C1 in blood cultures before the culture results are available.