>Thus, the target specificity of NK cells is greater than that
for CTLs.
Actually, NK cells have less specificity, they recognize all
kinds of things. They seem to be predominate in immune
surveillance, i.e. they clean up random cancer cells before they
get out of control. They also seem to have some regulatory
functions over their kindred T cells, perhaps maintaining the
balance between "normal" immunity and autoimmunity from a
hyperactive T cell stimulation.