NK / NKT Cells Natural Killer (NK) cells are important effector
lymphocytes of innate immunity that exhibit cytolytic activity
against a variety of allogeneic targets in a non-specific,
contact-dependent, nonphagocytic process which does not require
prior sensitization to antigen. NK cells share several
properties with conventional cytotoxic T cells (CTL), including
similar mechanisms for cytolysis. Cytolytic activity is mediated
by secretion of pore-forming proteins such as Granzyme B and
Perforin, serine proteases and other proteins. NK cytotoxic
activity is positively regulated by IL-2, IL-15 and interferons;
and is diminished by prostaglandins and TGF-beta. Natural Killer
T (NKT) cells represent a distinct lineage of T cells that
express an invariant alpha/beta T cell receptor (TCR) and share
a number of cell surface markers in common with NK cells. NKT
cells are activated by glycolipid antigens presented by CD1d.
Expression of CD160 and Valpha24Jalpha18 TCR can be used for the
identification of mouse and