自然殺手細胞是不需要事先免疫活化的內生性免疫反應中的一員。部分免疫細胞，如T 細胞及B 細胞之發展已被很詳盡的了解，然而，有關自然殺手細胞如何被產生的研究至今仍有限。自然殺手細胞主要是源自於人類骨髓內的造血幹細胞，在發展的過程中，自然殺手細胞能表現不同的細胞表面分子及細胞激素受體，這些表面分子是一個適當的標記，可用於判別自然殺手細胞的發展過程。另外，藉由細胞激素的刺激及轉錄因子的活化，自然殺手細胞才能逐漸進展至成熟，並發揮其細胞毒殺作用及促使干擾素的釋出。在這一篇文章中，我們總結一下目前對於自然殺手細胞的發展及分化的了解。有關於在細胞激素受體或轉錄因子缺陷的老鼠或病人的研究，也將在此討論。

Natural killer cells (NK cells) are one of the cellular mediators of innate immune responses,which does not require pre-immunization. Although the early stages in the development of humanT and B cells have been reasonably well defined, our knowledge about the early stages of humanNK cell development is very limited. NK cells are derived from adult human hematopoietic stemcells in the bone marrow. During development progression, NK cells are able to express variouscellular surface molecules and cytokine receptors,which are apposite markers to use to identify thestages of NK cell development. In addition, by using cytokine stimulation as well as transcriptionfactor activation, NK cells progress into mature stages, at which time they can be cytotoxic andproduce interferon- . In this review, we summarize our current understanding of NK celldevelopment and differentiation. Studies of mice or patients with gene deficiencies in cytokinereceptors or nuclear factors are discussed.