1454
Expression of Foxp3 in Peripheral Blood Mononuclear Cells of Pregnant Cows
Pregnancy has been shown to have great influence over the immune system through the modulation of immune cell types, dampening of the immune response, and display of overall immunodysfunction. It is a period through which the maternal immune response must tolerate long periods of exposure to foreign antigens produced by the growing fetus throughout gestation. To prevent loss of the fetus the maternal immune system will down regulate specific receptors, such as MHC, and push the system towards to tolerogenic state, as shown in mouse and woman studies. One of these strategies includes the increase in T-regulatory cells, which express the transcription factor FoxP3 and down regulate the immune response after activation. It has been previously shown in mice and woman that as gestation time lengthens the presence of T-regulatory cells increases both locally and systemically. However, this increase in T-regulatory cells has not been well defined in bovine pregnancy. The objective of this study is to determine the expression of FoxP3 transcription factor in CD4+ T-cells isolated from pregnant cows (n=5) and non-pregnant (n=5) at day 30 after AI; periparturient (n=5; 2-4 days before parturition) and nonpregnant (n=5) n lactating cows. CD4+ T-cells were isolated by magnetic sorting from selected cows and snap-frozen for RNA extraction and reserve transcription. Gene expression of FoxP3 and PXT-3 were determined by quantitative RT-PCR. Preliminary results show that there is a tendency (P=0.12) for decreased expression of FoxP3 on pregnant cows at Day 30 compared to cow close to parturition. The absence of difference in expression of FoxP3 between pregnant and non-pregnant cows could be due to sample time as well as small group sizes. Additionally, PTX-3 expression is downregulated (P=0.34) in the periparturient cows, although this was not significant. The decreased expression of PTX3 confirms that peripartum period represents a period of overall immunodysfunction as compared to early gestation. Overall, this study has the potential to identify cows that have higher conception rates due to an immunological system geared towards fetus tolerance.
Keywords:
Pregnancy, Regulatory Immune Responses, Dairy Cows