¹Fraser, K.P., ¹Gays, F., ¹Robinson, J.H., ²van Beneden, K.,  ²Leclercq, G., ³Vance, R.E., ³Raulet, D.H., and ¹Brooks, C.G.
The ¹Department of Microbiology and Immunology, The Medical School, Newcastle NE2 4HH, United Kingdom, ²The Department of Clinical Chemistry, Microbiology, and Immunology, Ghent University, University Hospital, B-9000 Ghent, Belgium, and ³Department of Molecular and Cell Biology and Cancer Research Laboratory, University of California at Berkeley, California 94720, U.S.A.

Eur. J. Immunol. 32, 868-78, 2002.
 

In the presence of appropriate cytokines and stimulants, progenitor cells present in the thymus develop into functional NK cells that express a variety of NK receptors but generally lack expression of any of the Ly49 molecules that have previously been examined.  We demonstrate here that during their development in vitro these NK cells acquire at least one previously uncharacterized member of the Ly49 family, most likely Ly49E, in a time-dependent and stochastic manner.  CD94 and NKG2 are also acquired in a stochastic manner but more rapidly than, and independently of, Ly49 molecules.  Throughout development CD94 is expressed at two different levels, the CD94^hi population accounting for all of the cells that stain strongly for NKG2 and with Qa1 tetramers.  In IL2-containing cultures CD94 is largely confined to NK1.1⁺ cells, but in cultures lacking IL2 and in vivo CD94 could be expressed in the absence of NK1.1.  IL4 displays a powerful and selective effect on the expression of NK receptors, blocking the acquisition of Ly49, CD94, and NKG2, but not NK1.1, by progenitor cells, and down regulating the expression of CD94 and NKG2 but not Ly49 or NK1.1 on more mature NK cells.  Key Data