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Related to Lymphocytes: Monocytes, Neutrophils



a variety of white blood cells (agranular leukocytes) in vertebrates and man.

Lymphocytes are spherical in shape and contain an oval nucleus, surrounded by ribosome-rich cytoplasm. Lymphocytes are distinguished, by size, as small (diameter, 4.5–6.5 microns [μ]), large (10–18 μ), and medium (6.5–10 μ). Cells of the small type constitute 95 percent of the total number of lymphocytes. Unlike lymphocytes of the large and medium types, these are incapable of mitosis. However, under the influence of phytohemagglutinin, they turn into large and medium lymphocytes, enter the mitotic cycle, and divide (this method is used in medical genetics for analyzing the cells’ chromosome apparatus). The majority of small lymphocytes are long-lived (in cases, surviving the life of the individual), circulating repeatedly between the lymph and the blood. The short-lived forms survive three to six days.

In mammals and man, lymphocytes are formed in the thymus gland, lymph nodes, spleen, bone marrow (short-lived only), and lymphoid-tissue aggregates (mainly along the digestive tract). The original form from which the lymphocytes of adult mammals develop is the hematopoietic stem cell, the daughter cells of which at first multiply in the thymus and then settle and multiply in the lymph nodes.

The principal functions of the lymphocytes are hematopoietic (certain lymphocytes presumably being capable of differentiation into other blood and connective-tissue cells), trophocytic (possibly serving as suppliers of nutrients and building materials to other cells), and immunological.

The destruction of lymphocytes (by ionizing radiation, antilymphocytic serum, immunodepressant medications) suppresses the body’s immunological reactivity. Advantage is taken of this in cases of tissue and organ transplant (to prevent rejection) and in the treatment of a number of diseases.


References in periodicals archive ?
However, the distinct, rare population of cells newly identified by Krummel s lab team persists in trying to activate tumor-targeting T lymphocytes, apparently with enough success despite their scarcity to make a difference in cancer outcomes.
Yeo, PhD, assistant professor in the Department of Cellular and Molecular Medicine and Institute for Genomic Medicine, said that researchers have been trying for a very long time to understand when and how T lymphocytes give rise to effector and memory cells during an infection.
Receiving the alarm, lymphocytes recognize the menace and call in a range of other cells that actually kill the invaders.
A Infants and young children have a dynamic immune system as supported by the presence of an increased number of lymphocytes at birth (around 5.
In asymptomatic stage of the disease the level of lymphocytes on the average was not differ from the data of the control group--32.
The activity of dehydrogenases in blood lymphocytes was calculated in enzyme units (1U=1mkmol/[min.
The category of Hodgkin lymphoma includes classical Hodgkin lymphoma (CHL) and the less common nodular lymphocyte predominant Hodgkin lymphoma (NLPHL).
The proliferation responses of lymphocytes in the presence of mitogens as well as PSM were determined on days 7, 14 and 21 after tumor inoculation by the method described by Masson and Gwanzura (1990).
Counting the lymphocytes using a Hemocytometer showed >95% of cell viability.
By impairing the development of adaptive immune responses needed for recovery, the apoptotic destruction of lymphocytes and dendritic cells could have a particularly adverse effect on disease outcome.

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