Development of immune response during typhoid fever in man.

The development of both humoral and cell-mediated immune responses (CMIR) to antigens prepared from Salmonella typhi was investigated in patients suffering from typhoid fever. The antibodies were determined by the standard Widal test while the leucocyte migration test was used for CMIR. These immunological parameters were correlated with the duration of illness, the duration of chloramphenicol therapy and the severity of the illness. It was found that CMIR appeared after the first week of illness in uncomplicated cases of typhoid fever, where as it remained negative in the patients who had complications. The antibody titres were similar in the two groups. On further follow up of complicated cases, the clinical recovery coincided with the development of CMIR. It may be concluded that for recovery in typhoid fever CMIR is more important than antibodies.