Dynamics of IgG1 and IgG2 subclass response in dogs naturally and experimentally infected with Ehrlichia canis

Immunoglobulin (Ig) G subclasses were measured in dogs naturally and experi mentally infected with Ehrlichia canis using enzyme-linked immunosorbant as say (ELISA). In this study, a higher IgG2 subclass response was noticed to natural and experimental E. canis infection in dogs. Anti-E. canis-IgG2 opt ic density (OD) values were found to be significantly higher than anti-E. c anis-IgG1 during the different phases of the disease, and no differences in the IgG subclass responses to E. canis infection were found between sympto matic and asymptomatic dogs. Doxycycline treatment, which eliminated the ri ckettsia in three of four persistently infected dogs, had no noticeable inf luence on the E. canis-IgG subclass OD values during the treatment period. In order to facilitate the study, an ELISA for the detection of anti-E. can is IgG was developed and was shown to be sensitive and specific for E. cani s-IgG, and in a significant correlation with the indirect immunofluorescenc e antibody test. (C) 2001 Published by Elsevier Science B.V.