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This is a list of immune cells, also known as white blood cells, white cells, leukocytes, or leucocytes. They are cells involved in protecting the body against both infectious disease and foreign invaders .
A lymphocyte is a type of white blood cell (leukocyte) in the immune system of most vertebrates. [1] Lymphocytes include T cells (for cell-mediated and cytotoxic adaptive immunity), B cells (for humoral, antibody-driven adaptive immunity), [2] [3] and innate lymphoid cells (ILCs; "innate T cell-like" cells involved in mucosal immunity and homeostasis), of which natural killer cells are an ...
Some leukocytes (white blood cells) act like independent, single-celled organisms and are the second arm of the innate immune system. The innate leukocytes include the "professional" phagocytes (macrophages, neutrophils, and dendritic cells). These cells identify and eliminate pathogens, either by attacking larger pathogens through contact or ...
Since antigen levels are usually low, contact in blood circulation would be unlikely. Therefore, T cells need a region where they can go to sample foreign antigens that have entered the body. When an APC, such as a dendritic cell, binds a foreign antigen; it becomes activated and moves into the lymph nodes (sites for antigen sampling by T cells ...
Although lymphocytes are usually considered mature, as seen in blood tests, they are certainly not inert. Lymphocytes can travel around the body wherever there is a need. When such needs arise, new rounds of downstream lymphopoiesis, such as cell multiplication and differentiation, may occur, accompanied by intense mitotic and metabolic activity.
An excess of white blood cells is usually due to infection or inflammation. Less commonly, a high white blood cell count could indicate certain blood cancers or bone marrow disorders. The number of leukocytes in the blood is often an indicator of disease, and thus the white blood cell count is an important subset of the complete blood count.
Neutrophils extravasate from blood vessels to the site of tissue injury or infection during the innate immune response.. In immunology, leukocyte extravasation (also commonly known as leukocyte adhesion cascade or diapedesis – the passage of cells through the intact vessel wall) is the movement of leukocytes (white blood cells) out of the circulatory system (extravasation) and towards the ...
Lymph nodes contain lymphocytes, a type of white blood cell, and are primarily made up of B cells and T cells. [5] B cells are mainly found in the outer cortex where they are clustered together as follicular B cells in lymphoid follicles, and T cells and dendritic cells are mainly found in the paracortex .