The Research On The Relationship Between B1-a Cell And B2 Cell In Development And Differentiation

ObjectiveAccording to the development of B cells, B lymphocytes can be divided into two groups:B1 cells and B-2 cells. According to whether CD5 molecules can be express, B1 cells can be divided into two subsets:Bl-a cell(CD5+) and B1-b cell(CD5-). B1 cells,which developed from the early precursors, distributed in the spleen at Embryos and after birth, and mainly engaged in adulthood peritoneal, pleural omental and tonsil, etc.while B1 cells are rare in peripheral blood and lymph organs in adult. Almost not dependenting on bone marrow sources, B1 cells,which have important functions and can updated independently,is a kind of long-lived cells.The relevant research suggested that there is a big difference between B1 cells and B2 cells in origin, differentiation, surface mark and gene expression.Especially in the development and differentiation, there has been an controversion. The current research shows that: (DB cells has been divided into different lineages in the develpoment of progenitors. Thece cells were taken separately from embryonic liver and adult bone marrow.which has already been an difference both in time and space.As a result, the development of B cells may has a certain relationship with their environment. (2)B cells may developed into different directions in the late differentiation due to a mediated signal, while these cells is belong to the same lineage at the progenitor stage. If we provide certain environment or interference factors, B1 cells can be transformed to B2 cells?③B1 cells appeared relatively earlier than B2 cells. Studies show that the B cells produced in pregnancy 8.5-9.0 days near the aorta (PAS) dirty walls were CD5+CD45RlowsIgMhi phenotype, this phenotype was so called B1-a cells, which is not B1-b or B2 cells. Therefore, we think the first developmen wave of B cell was B1-a cells.However, B2 cells can be transformed to B1 cells in certain conditions. This transformation belongs to atavism. Then B1 cells may be transformed to B2 cells under certain conditions,which shoud be in our further study. We provide environment via establishing bone marrow in vitro, in which B1 cells purified by FACS(facial action coding systerm) can be cultured and developed. At the first to sixth day, we will make a detection by FACS to observe whether B1-a cells could be transformed to B2 cells.MethodsTaking 15 C57BL newborn mouse and extracting lymphocytes from splenic, which would be markered by APC-anti-mouseIgM, PE-CY5-anti-mouseCD5, PE-anti-mouse IgD fluorescent antibodys. B1-a cells purified by FACS,would be marked by CFSE and then transfered into a space micro-environment via establishing bone marrow form C57BL/6 weeks mice,further cultuerd in vitro. At the first to sixth day, we will use PE-anti-mouse IgD fluorescent antibody markers and make a detection by FACS to observe whether B1-a cells could be transformed to B2 cells.ResultAt the second to sixth day, we will make a detection by FACS.We can detect B 2 cells with CFSE maked. B1-a cells could be transformed to B2 cells. The conversion percentage is respectively,52.93±1.93%(1d),26.98±2.94%(2d). The conversion percentage of the former(1d) was more than the latter(2d). The results was proved had statistical difference (P<0.01).DiscussionThe development peak of B1 cells was in period of embryonic,and decreased obviously in adult. Therefore,extracting splenic lymphocytes from new born 1d mice, from which we sorting B1-a cells and then marked by CFSE.These cells were cultured in a space bone marrow micro-environment in vitro.At the first to sixth day, we will make a detection by FACS. The results prove that B1-a cells could be transformed into B 2 cells in vitro.Both in differentiation and development,they has great relevance. But B1-a cells purified by FACS,may contained some B 2 cells.Therefore,the results may be false positive,and we should make more progress in the research to make the rults more validity. Conclusion1.The results prove that B1-a cells purified by FACS could be transformed into B2 cells in vitro.2. The conversion percentage is respectively,52.93±1.93%(1d),26.98±2.94%(2d). The conversion percentage of the former(1d) was more than the latter(2d). The results was proved had statistical difference (P<0.01).