Functional role of CD43 in immune system

CD43是造血细胞表面主要的唾液蛋白，其胞外结构域严重o -糖基化。CD43在造血系统中的功能作用尚不完全清楚；然而，有研究表明CD43可能在细胞间排斥和修饰t细胞增殖和活化中起作用。为了分析CD43在b系细胞中的生物学效应，我们将小鼠CD43 cDNA转染到CD43^- b细胞淋巴瘤WEHI 231中，并与亲本细胞系、人CD8转染细胞系和由CD43^+克隆建立的CD43^-复归细胞系的生长和存活进行了比较。这些结果支持了CD43可能在b系细胞存活中起一定作用的观点，可能通过抵抗细胞凋亡和细胞周期的进展来反映。这些结果也支持了CD43与其配体（无论是在WEHI 231表面表达还是从其分泌）之间的相互作用对CD43的生物学效应起作用的观点。为了表征CD43在B细胞存活和激活中的作用，我们建立了两只CD43转基因小鼠，并使用了一个拷贝数高于另一个的品系。体外LPS刺激后，CD43转基因小鼠脾细胞中CD43的表达上调约为非转基因小鼠的10倍，其中CD43转基因小鼠脾细胞产生的lgM抗体约为非转基因小鼠的3倍。在用DNP-KLH进行一次免疫时，转基因小鼠产生的lgM抗体比非转基因小鼠高2-3倍。体外和体内的结果与CD43的表达可能在lgM抗体形成细胞的分化和生存中发挥一定作用的观点相一致。进一步的免疫小鼠细胞动力学分析正在研究中。

CD43 is a major surface sialoprotein on hemopoietic cells, whose extracellular domain is heavily O-glycosilated.The functional role of CD43 in the hemopoietic system is not fully understood ; however, it has been suggested that CD43 may have a role in cell-cell repulsion and in modifying T-cell proliferation and activation.In order to analyze the biological effect of CD43 in B-lineage cells, we transfected murine CD43 cDNA into a CD43^- B-cell lymphoma, WEHI 231, and the growth and survival in culture were compared to those of a parental cell line, human CD8 transfectants, and CD43^- revertants established from CD43^+ clones.The results support the notion that CD43 may have some role in cell survival of B-lineage cells, probably reflected by the resistance to apoptosis and progression of the cell cycle.The results also support the notion that interaction between CD43 and its ligand, either expressed on the surface of or secreted from WEHI 231 has a role for the biological effect of CD43.In order to characterize the role of CD43 in B cell survival and activation, we established two CD43 transgenic mice and used one of the line who carries copy numbers higher than another.Expression of CD43 was up-regulated in splenocytes of CD43 transgenic mice at the level approximately 10 times higher than that of non-transgenic mice upon stimulation with LPS in vitro, in which splenocytes of CD43 transgenic mouse produced lgM antibodies approximately 3 times above the level of non-transgenic mose.In primary immunization with DNP-KLH,the transgenic mice produced lgM antibodies 2-3 times above the level of non-transgenic mice.The results in vitro and in vivo are compatible with the idea that the expression of CD43 may play some role in differentiation into lgM antibody-forming cells and their survival.Furthe analysis of cell dynamics in immunized mice is now inder investigation.