Lymphoid Hematopoiesis and Lymphocytes Differentiation and Maturation

Abstract

Abstract Lymphocytes belong to the lymphoid lineage and are considered as divergent from other blood cells lineages as those from the myeloid or erythroid lineage. Lymphoid hematopoi- esis is not trivial, because although lymphocytes are found in the bloodstream and their precursor originates in the bone marrow, they mainly belong to the separate lymphatic system, which interacts with the blood circulation. We will discuss B cell differentiation in the bone marrow and the later stages of maturation in secondary lymphoid tissues, besides the B cell profiles in interfollicular, perifollicular, and follicular areas. In addition, we will also discuss T-cell precursor and natural killer cells derivation in the marrow. Furthermore, we will also discuss T-cell precursor migration to thymus, differentiation, rearrangement, thymic selection, involved transcription factors, and, finally, T-cell pro- files and subsets in secondary lymphoid organs. We will provide flow cytometry plots showing strategies to identify and characterize NK, T and B lymphocytes and their subsets in circulation. Furthermore, we will provide illustrations to help the reader to understand and visualize the information provide over the chapter. Furthermore, the comprehension about lymphocytes and their contribution to the immune response will favor their appli- cation in developmental hematology and immunology. These topics are very important for the continuous development of knowledge.