PARENT SESSION
Reproductive Immunology

EXPRESSION OF THE ANTIVIRAL PROTEIN MX IN PERIPHERAL BLOOD MONONUCLEAR CELLS (PBMC) IN BRED, NON-PREGNANT, AND EARLY PREGNANT EWES.

Yankey, Stephanie¹, Hicks, Brady¹, Carnahan, Kevin¹, Assiri, Abdullah³, Sinor, Stacy¹, Kodali, Kiran¹, Stellflug, John^1,2, Ott, Troy¹, ^{1 3 2}

ABSTRACT- It is widely accepted that the ruminant pregnancy recognition signal, Interferon-tau (IFNt), acts locally on the endometrium to block luteolysis. Attempts to measure increased IFN activity in the uterine venous or lymphatic drainage have been unsuccessful. A number of IFNt-induced genes are up regulated across the entire uterine wall during early pregnancy. This suggests that the high levels of IFNt produced by the periimplantation conceptus may affect components of the circulating immune system that reside in or migrate through the endometrial wall. This study examined the effect of early pregnancy on Mx expression in the PBMC in sheep. In experiment one, blood was collected by jugular venipuncture from 120 ewes at D 26 post artificial insemination (AI=D 0). PBMC were isolated by centrifugation and Mx mRNA levels were examined by Northern and slot blot hybridization. Northern blot analysis confirmed the presence of 2.5 Kb Mx mRNA in PBMC from both pregnant and non-pregnant ewes. Slot blot analysis showed a two-fold increase of Mx mRNA (p<0.01) in pregnant versus non-pregnant ewes at D 26 post AI. Levels of Mx mRNA at D 26 were affected by the number of conceptuses present with ewes carrying twins or triplets expressing greater levels of Mx mRNA compared to those carrying singles (p<0.05). Experiment two examined the temporal expression pattern of Mx mRNA during early pregnancy. PBMC were isolated from blood samples taken at AI, and every three days from D 9 to D 30. Pregnancy was confirmed by ultrasound and PSPB RIA at D 30. Slot blot analysis showed a four-fold increase (p<0.01) in Mx mRNA levels of pregnant versus non-pregnant ewes at D 15. Mx mRNA levels in pregnant ewes remained elevated through D 30. These results suggest that early pregnancy alters gene expression in the maternal circulating immune system and may provide a mechanism for early identification of bred, non-pregnant animals following insemination. Supported by USDA-FAH #IDA02-AHD98 to T.L.O.

KEY WORDS: Mx, interferon, pregnancy, PBMC