Lymphocytes are mononuclear leukocytes whose nuclei do not become lobulated during maturation.
In a counting of normal blood, they constitute the second lagest group of leukocytes, after the neutrophils. There are several subtypes of lymphocyte but they but they cannot be distinguished in routine histological sections. They can be recognized by several techniques, such as immunocytochemistry.
Among other functions, the lymphocytes are responsible for specific recognition of antigen, production of immunoglobulins (antibodies), and triggering and control of immune responses in the body.
Lymphocytes are spherical cells, usually small measuring about 7 µm in diameter. Their nucleus is spherical and occupies most of the cell volume. Usually a thin layer of cytoplasm can be seen surrounding the nucleus. For this reason, lymphocytes are usually recognized in sections or blood smears by their nuclei.
Several lymphocytes can be seen in the upper figures. Their nuclei become highlighted in dark blue. In some lymphocytes, a rim of cytoplasm can be seen around the cytoplasm, highlighted in green. See also the lymphocytes highlighted in the lower figure.
More lymphocytes can be seen by clicking on: page 12-14 and page 12-15.
Connective tissue. Staining: HE. Magnification: medium.