Antibody response to POMP90-3 after intranasal infection in sheep with Chlamydophila abortus

Abstract

Ovine enzootic abortion (OEA), caused by infection with gram negative bacteria Chlamydophila abortus (C. abortus), is one of the major causes of infectious abortion in sheep worldwide. So far there are only diagnostic tools available to confirm the disease after abortion. The purpose of this study was to measure and monitor the IgG antibody response against polymorphic outer membrane protein POMP90-3 (which is a part of a protein present on the surface of C. abortus) during the development of a model of latency and see if there are possibilities to predict abortion, using the indirect enzyme-linked immunosorbent assay rOMP90-3 iELISA (developed at Moredun Research Institute, Edinburgh). Three groups were intranasally infected with different doses of C. abortus before they were mated. A negative control group was intranasally challenged with uninfected yolk sacs before mating and a positive control group was infected subcutaneous over the left prefemoral lymp node at 10 weeks of gestation (the standard method of infection in OEA studies). The antibody responses of all groups were followed for the first 13 months. During the latent phase a significant difference in antibody titers between groups 1 and 2 and the control group was detected. This shows that it is possible to detect an infection early in gestation or may be even before pregnancy. Although due to huge variations between animals, the test is perhaps not appropriate for that purpose. The intranasal route of infection before mating seems to be a better model for natural infection than the traditional method, subcutaneous over the left prefemoral lymph node. The intranasally way of infection shows the latency period and gives a higher percentage of abortion.