A. Verdugorodriguez et al., DETECTION OF ANTIBODIES AGAINST SALMONELLA-TYPHI OUTER-MEMBRANE PROTEIN (OMP) PREPARATION IN TYPHOID-FEVER PATIENTS, Asian Pacific Journal of Allergy and Immunology, 11(1), 1993, pp. 45-52
An indirect ELISA was used to detect antibodies against outer membrane
protein preparations (OMPs) from Salmonella typhi. Sera from patients
with a definitive diagnosis of typhoid fever (TF) gave a mean absorba
nce reading, at 414 nm, of 1.52 +/- 0.23 as compared to 0.30 +/- 0.11
for sera from healthy individuals. This gave a positive to negative ra
tio of absorbance readings of approximately 5.1. Suspected TF patients
(no isolation of S. typhi), with positive and negative Widal titers h
ad mean absorbance readings of 1.282 +/- 0.46 and 0.25 +/- 0.19, respe
ctively. Sera from patients with leptospirosis, rickettsial typhus, de
ngue fever, and other infections gave mean absorbances of 0.20 +/- 0.0
8, 0.24 +/- 0.08, 0.27 +/- 0.08, and 0.31 +/- 0.16, respectively. The
sensitivity, specificity, positive and negative predictive values were
100%, 94%, 80% and 100%, respectively. The antibody response detected
in the definitive TF cases was predominantly IgG in nature and no cro
ss-reactivity was seen with OMP preparations extracted from E. coli. V
ariable reactivity was noted with OMP preparations obtained from other
Salmonella spp. Three major OMPs are presented in the antigen prepara
tion and strong binding of positive sera was detected to all three ban
ds.