Proteomic changes during the B cell development.

An antibody-secreting B cell is derived from a lymphoid stem cell through a series of developmental stages: progenitor B cell (pro-B cell), precursor B cell (pre-B) cell, immature B cell and mature B cell stage. The gene rearrangement of antigen receptor genes and their expression on the cell surface are crucial regulation steps cells to develop to the next stage. This control mechanism occurs at the sequential manner during the B cell development. Proteomic approach using two-dimensional (2-D) gel electrophoresis and mass spectrometry makes possible to analyze the expression pattern of total proteins at each developmental stage and isolate proteins differentially expressed in B cells. Some transcriptional factors such E2A and Pax5 are expressed at the earlier stages of B cell development and repressed at later developmental stages. RAD52-related protein and chromatin assembly factor 1 are dominantly expressed at early B cells undergoing DNA rearrangement. These comparative analyses of total proteins in each B cell can provide some crucial information to understand the molecular basis of B cell ontogeny.