Assessment of reactivities of Typhoid fever sera against outer membrane protein preparations from strains of salmonella typhi in Jakarta

An attempt was carried out to assess reactivity of sera from patients with typhoid fever against outer membrane protein (OMP) preparations derived from local strain of Salmonella typhi OMPs from 10 clinical isolates of S. typhi were isolated by sonlcation and through the use of buffer containing Triton X-100 2%. SDS-PAGE of these OMPs showed six different electrophoretic profiles in which major proteins with molecular weight (MW) 38, 37 and 34 IcDa corresponding to OmpC, OmpF and OmpA respectively were present in most of the OMPs. Three isolates ofS. typhi, however, did not show the 34 kDa protein. Although not as prominent, polypeptide with MW 20.5 kDa was observed in all OMPs while polypeptide with MW 25 and 29 kDa in 4 and 6 OMP preparations respectively. Immunoblotting of the OMPs with immunised rabbits’sera showed strong reactivity against the porins, the 37, 38 kDa, and the 29 kDA polypeptide. Sera from patients with typhoid fever contained IgM antibodies which did not react with the porins and the OmpA, however, they showed reactivity to the minor polypeptides.