The development of lymphocytes is intricate and has different qualities including limitation to essential lymphoid organs like the spleen, thymus, and thymus organ B-cell development requires bone marrow Lymphocyte development in the thymus. Positive choice with the end goal of guarantee all cells have functional receptors [1, 4] Proliferation in order to extend the pool of potential lymphocytes consider wide insurance against various sorts of antigens Negative determination to eliminate cells that target self-antigens safeguard against autoimmunity There are numerous components to expand variety during lymphocyte development, for example, Irregular recombination of hereditary material during substantial hyper mutation after antigen openness occurs in only B-cells Irregular nucleotide expansion to hyper variable areas by the protein TdT.