From Biology-Online Dictionary | Biology-Online Dictionary


noun, plural: lymphocytes

The white blood cell of the blood derived from the stem cells of the lymphoid series of vertebrates


Lymphocytes are a type of white blood cells. They may be grouped into two: small and large lymphocytes. The small lymphocytes include B lymphocytes and T lymphocytes. The B lymphocytes are involved in the production of antibodies in the humoral immune response. The T lymphocytes participate in the cell-mediated immune response. The large lymphocytes include the natural killer cells, i.e. cytotoxic cells involved in the innate immune response of vertebrates.

Lymphocytes are derived from the stem cells of the lymphoid series, thus the name. The process of producing lymphocytes is called lymphopoiesis. Histologically, a mature lymphocyte is characterized by the large nucleus, scanty cytoplasm, and the absence of distinct nucleolus and organelles.

Lymphocyte count is typically part of the complete blood cell count. It is expressed as the percentage of lymphocytes to the total number of white blood cells. An increase in the normal range of lymphocytes is known as lymphocytosis whereas a decrease is called lymphocytopenia.

Word origin: French lymphe, from Latin lympha (water, water nymph), from Ancient Greek númphē (nymph) + New Latin cyta, from Ancient Greek kútos (vessel, jar)

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  • lymphocytic (adjective, of, pertaining to, or relating to a lymphocyte)