Kinetics of the complement fixing and immunofluorescent antibody response in experimental chlamydiosis in ewes

Normal, 70 days pregnant ewes were inoculated i.v. with a chicken embryo grown Chlamydia psittaci strain. The ewes presented a biphasic febrile curve and aborted 30 to 68 days after inoculation. Chlamydiae were isolated from aborted fetuses and from vaginal swabs. Ewes developed CF and IF antibodies titrating 1:320 to 1:1024 two to three weeks after inoculation. A second antibody rise occurred one to two weeks before or after abortion and reached titers of 1:640 to 1:1024. Immunoglobulin fractions from the serum of the ewes were also tested by CF and IF. IgG antibodies were detected by both methods and the trend of their kinetics was similar to that of whole serum. IgM antibodies were present in very low titers in the immunoglobulin fractions of some of the animals. CF and IF were equally sensitive in detecting anti-Chlamydia antibodies in whole serum or immunoglobulin fractions.