Differential Expression Of Bovine BoLA-NC1 In Pregnant Dairy Cows And Neonatal Calves

Experiments in human and mouse showed that directly or indirectly immune major histocompatibility complex (MHC) can affect the quality of gametes and embryo development. Bovine MHC was named as bovine leukocyte antigen (BoLA). According to the different genotypes, BoLA was divided into class I and class II and III. On the immunological point, pregnancy is similar to organ transplantation, maternal immune system recognize the embryo with a paternal antigens and generate protective immune responses, until fetal disengagement. Once the balance of maternal-fetal interactions was destroyed, it would result in pathological pregnancy, such as unknown cause miscarriage. Protect the embryo from the mother's immune system rejection is significant for the successfully establishment and maintenance of pregnancy. BoLA-NC1 was a nonclassic gene of BoLA-I. This article basing on the gene level, had studied the normal breeding cows BoLA-NC1 differential expression at different pregnant stages, which was helpful to understand the way to establish and maintain immunologic pregnancy.Methods:collecting the blood samples and placental tissue samples from young cows, pregnant cows in first, second trimester and one week before parturition, neonatal calf ear tissue and placental tissue (all samples were collected from the dairy farm of Shanghai dairy cattle Institute); extracting the total RNA, getting the cDNA by reverse transcription, cloning BoLA-NC1 gene by general PCR, verifying the gene by sequencing, quantizing the expression of BoLA-NC1 gene by RT-PCR. Relative quantitative experiments through comparison of CT values determined the expression level of cattle MHC-I protein antigen from normal pregnant cows of different stages and placental tissue.Results:compared with the expressive level of BoLA-NC1 in replacement heifer, gene level in early pregnancy was much higher (P<0.01), but no significant difference (P>0.05) in mid-gestation, and significantly high in parturition (P<0.01); the expression in neonatal calves and placenta tissue is lower (P<0.01).Conclusion:Differential expression of cows'non-classical gene BoLA-NC1 of BoLA-I in normal pregnancy and the newborn calves reflected the regulation of maternal immune system. This gene expression and classic BoLA-I genes in cows, relatively made different stages of pregnancy express security cow establish, maintain of pregnancy until delivery. The study BoLA-NC1 from the molecular level for cow pregnancy immune mechanism research has important significance. It is an inhibitor of immune rejection genes, his expression is not only caused by antigen mediated by the pregnancy itself, but by many immune factors, and participated in jointly. As one member BoLA-NC1 genes, it cut pregnancy immune response, inducing immune tolerance, maintaining normal pregnant process.