Table 1.
Innate cell characteristics | NK cell characteristics | Adaptive cell characteristics | |
---|---|---|---|
Cell lineage | Myeloid, lymphoid | lymphoid | lymphoid |
Genetic encoding of major known recognition receptors | Germ-line genes | Germ-line genes | Rearranging genes |
Clonally distributed expression of recognition receptors | No | Yes (in some casesa) | Yes |
Multiple recognition receptors can independently activate individual cells | Yes | Yes | No |
Cells undergo education processes to prevent autoreactivity | Unknown | Yes | Yes |
Receptors from the Ly49 and NKG2A-C families of genes, each of which include some activating and some inhibitory members, are expressed in a clonally distributed fashion, whereas receptors such as NKp46 and NKG2D are uniformly expressed.