牛における早期妊娠因子 (Early Pregnancy Factor) の検出とその臨床応用

Abstract

Early pregnancy factor (EPF) was first detected by Morton et al. in the maternal serum within 24-48 h after fertilization, and they demonstrated by the rosette inhibition test that EPF augments the immunosuppressive action of an antilymphocyte serum (ALS). Ever since, EPF has been detected in sera of various animal species. In cattle, EPF has also been detected, but detailed reports are few, and supplementary examination of clinical applications has not been published. In the current investigation, we first tested sera from six cattle 15 days after artificial insemination and from six nonpregnant cattle, and analyzed rosette inhibition titers (RIT) between pregnancy and nonpregnancy. As a result, statistically significant difference was noted between pregnancy and nonpregnancy. Secondly, for clinical application, we measured the EPF activity in pregnant sera from day 2 to 38 after artificial insemination. The EPF activity was first demonstrated at day 2 after artificial insemination, and it persisted to day 38 when the diagnosis by conventional pregnancy tests was able to performed. Then the EPF transition of recipient cattle after embryo-transfer was investigated. In two recipient cattle, no EPF activities could be detected by day 14 after artificial insemination, and they were diagnosed as nonpregnancy. In the other two, EPF activity was continued, and pregnancy was clinicall diagnosed. Another one showed EPF activity by day 15, but the activity then disappeared, which suggested an early embryonic death.These results demonstrate that it is capable to diagnose pregnancy by EPF, and that it is useful to monitor viable embryos in cattle