killer cell

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Any of various large differentiated T cells that recognize and lyse target cells bearing a specific foreign antigen, usually by infection with a virus, and that also function in defense against cancer cells. Also called cytotoxic T cell, killer T cell.

A lymphocyte that develops in the bone marrow and lacks the characteristic surface markers of the B and T lymphocytes. Killer or null cells represent a small proportion of the lymphocyte population. Stimulated by the presence of an antibody, null cells can attach certain cellular targets directly and are known as natural killer cells.

A large differentiated T cell that attacks and lyses target cells bearing specific antigens. Also called cytotoxic T cell, killer T cell, null cell.

The noun has one meaning:

Meaning #1: T cell with CD8 receptor that recognizes antigens on the surface of a virus-infected cell and binds to the infected cell and kill it
  Synonyms: CD8 T cell, CD8 cell