natural killer cell

n.
A lymphocyte that is activated by double-stranded RNA or lymphokines and fights off viral infections and tumors without evident antigenic specificity.

NK cells

A class of large granular lymphocytes that recognize and kill a variety of cancer cells and virus-infected cells. NK cells are an important part of the innate immune system, providing a major first-line defence against viral infection. NK cell activity is decreased in a number of conditions associated with reduced immune competence. including physiological stress. The total number of natural killer cells decreases for up to 24 h after severe exercise. Although this may reduce the total activity of natural killer tells and make athletes mute vulnerable to infection for a brief period following exercise, the activity of individual natural killer cells actually increases.

n.

(Abbr. NK cell) A killer cell that is activated by double-stranded RNA and fights off viral infections and tumors.