An enzyme linked immunosorbent assay for detection of antibodies to Corynebacterium kutscheri in experimentally infected rats.

Abstract

An enzyme-linked immunosorbent assay (ELISA) which detects rat antibody to Corynebacterium kutscheri was developed and compared with a tube agglutination assay in two infectivity studies. In four groups of rats inoculated intratracheally with 100-fold dilutions of Corynebacterium kutscheri , mortality, lesions, and recovery of Corynebacterium kutscheri were confined to the two highest dose groups. Five of 17 (29%) test rats seroconverted within 14 to 21 days post-inoculation as assayed by ELISA; four of these five (80%) seroconverted within 42 to 98 days post-inoculation as assayed by tube agglutination. ELISA titers were one to 16 times greater than tube agglutination titers. In 15 rats challenged intranasally with 6.9 X 10(6) Corynebacterium kutscheri , clinical signs were observed in one of 15 (6.7%), and bacteriologic and histopathologic evaluations detected exposure to Corynebacterium kutscheri in three of 14 (21.4%) and one of 14 (7.1%) of the rats, respectively. Fourteen days post-inoculation, seroconversion was observed in 14 of 15 (93.3%) by ELISA, as compared to six of 15 (40%) by tube agglutination (p less than 0.001). The ELISA was more sensitive than tube agglutination through 21 days post-inoculation, while sera assayed 33 to 53 days post-inoculation had comparable titers in both assays. Specificity studies using four other Corynebacterium sp indicated that the Corynebacterium kutscheri ELISA cross reacted with two of four (50%) sets of corynebacterial antisera (Corynebacterium ulcerans and Corynebacterium equi) prepared in rats, whereas no cross reactivity was observed by tube agglutination.