Detection of serum antibodies against XXXX in @entity221 by enzyme-linked immunosorbent assay.

@entity1 @entity30953 @entity221 @entity1641
An indirect enzyme-linked immunosorbent assay (ELISA) was developed which was specific and sensitive in detecting antibodies to @entity30953 in @entity221 ( @entity221 ). The ELISA antibody titers were correlated with the indirect fluorescent antibody (IFA) titers. @entity30953 propagated in @entity1 histiocyte culture was purified on renografin gradient and the band of the organisms at a density of 1.182 g/ml was used as antigen. ELISA antibody titers were determined through computer assisted analysis, the observed antibody titers were derived by serial serum dilutions and using a resultant standard curve the predicted antibody titers were obtained from a single serum dilution. The standard curve had a correlation coefficient of 0.8975. The observed and predicted antibody titers were in good agreement, as the respective titers fell within a two-fold range. There was a good correlation between ELISA and IFA test results, but the ELISA titers were several times higher. In experimental infections of @entity1641 produced with the infected @entity1641 whole blood and the Ehrlichia infected macrophage culture, the antibodies were first detected in two weeks and one week postinoculation (PI), respectively. In both cases the titers reached a peak in about 4 weeks PI with a mean titer of 1:16558 and 1:4030, respectively. The antibody titers of the convalescent sera of field cases of @entity221 were comparatively lower than the experimentally infected @entity1641 .
