B cell

beta cell, cell in the pancreatic islets which produces and secretes insulin (Physiology); type of lymphocyte produced in the bone marrow, precursor of antibody-producing plasma cells (Immunology)

B cells are lymphocytes that play a large role in the humoral immune response as opposed to the cell-mediated immune response that is governed by T cells. The principal function of B cells is to make antibodies against soluble antigens. B cells are an essential component of the adaptive immune system.
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Noun
1. a lymphocyte derived from bone marrow that provides humoral immunity; it recognizes free antigen molecules in solution and matures into plasma cells that secrete immunoglobulin (antibodies) that inactivate the antigens
(synonym) B lymphocyte
(hypernym) lymphocyte, lymph cell

A white blood cell that makes antibodies and is an important part of the immune system. B cells come from bone marrow. Also called B lymphocyte. 

An antibody-producing leukocyte.