Yankee T M, Clark E A
Primate Center, University of Washington, Seattle 98195-0001, USA.
Rev Immunogenet. 2000;2(2):185-203.
Signaling events arising from the B cell antigen receptor (BCR) complex are critical for the normal progression of a B cell through its stages of maturation. These stages are characterized by the generation and expression of BCR components. Initially, the heavy chain is formed and expressed along with the surrogate light chain and VpreB. This pre-BCR may initiate events that induce the cell to generate the light chain molecules. Proper expression of these molecules triggers the cell to develop into a mature B cell. If a key signal is absent at any stage of B cell development, maturation ceases, and either the defects are corrected or the cell undergoes apoptosis. A deficiency in the expression of several intracellular proteins required for these signaling events leads to the arrest of B cell development. Advancement to specific stages of maturation relies on a particular intensity of signal through pathways leading to the activation of a set of transcription factors. These pathways include the calcium and MAPK family pathways. Factors such as the concentration and avidity of the antigen, the coligation of co-receptors, and the formation of signaling complexes dictate the intensity of these signals and thereby the fate of the B cell at each stage of development.
源自B细胞抗原受体（BCR）复合物的信号事件对于B细胞在其成熟阶段的正常进展至关重要。这些阶段的特征是BCR组分的产生和表达。最初，重链与替代轻链和VpreB一起形成并表达。这种前BCR可能引发诱导细胞产生轻链分子的事件。这些分子的正确表达触发细胞发育成成熟的B细胞。如果在B细胞发育的任何阶段缺少关键信号，成熟就会停止，要么缺陷得到纠正，要么细胞发生凋亡。这些信号事件所需的几种细胞内蛋白质表达的缺陷会导致B细胞发育停滞。向特定成熟阶段的进展依赖于通过导致一组转录因子激活的途径的特定信号强度。这些途径包括钙和MAPK家族途径。诸如抗原的浓度和亲和力、共受体的共结合以及信号复合物的形成等因素决定了这些信号的强度，从而决定了B细胞在发育各阶段的命运。
