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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 ...
Of the three B cell subsets, FO B cells preferentially undergo T cell-dependent activation while MZ B cells and B1 B cells preferentially undergo T cell-independent activation. [ 16 ] B cell activation is enhanced through the activity of CD21 , a surface receptor in complex with surface proteins CD19 and CD81 (all three are collectively known ...
B cells acquire antigen directly from the afferent lymph. If a B cell binds its cognate antigen it will be activated. Some B cells will immediately develop into antibody secreting plasma cells, and secrete IgM. Other B cells will internalize the antigen and present it to follicular helper T cells on the B and T cell zone interface.
The T cell-dependent processes are subdivided into primary and secondary responses: a primary response (meaning that the T cell is present at the time of initial contact by the B cell with the antigen) produces short-lived cells that remain in the extramedullary regions of lymph nodes; a secondary response produces longer-lived cells that ...
The cell is the basic structural and functional unit of all forms of life. Every cell consists of cytoplasm enclosed within a membrane; many cells contain organelles, each with a specific function. The term comes from the Latin word cellula meaning 'small room'. Most cells are only visible under a microscope.
To keep cells alive during observation, the microscopes are commonly enclosed in a micro cell incubator (the transparent box). Live-cell imaging is the study of living cells using time-lapse microscopy. It is used by scientists to obtain a better understanding of biological function through the study of cellular dynamics. [1]
Similar to B1 B cells, MZ B cells can be rapidly recruited into the early adaptive immune responses in a T cell-independent manner. [9] The MZ B cells are especially well-positioned as the first line of defense against systemic blood-borne antigens that enter the circulation and become trapped in the spleen. [10]
Cell theory states that cells are the fundamental units of life, that all living things are composed of one or more cells, and that all cells arise from preexisting cells through cell division. [41] Most cells are very small, with diameters ranging from 1 to 100 micrometers and are therefore only visible under a light or electron microscope ...