<prompt> CD 56 is a marker for which cellsB LymphocytesT LymphocytesEosinophilsNK cells  <response>: NK-cells :- Key component of the innate immune system . Lack T-cell receptors or immunoglobulins. Cell surface markers include CD2, CD56, and CD16 . Identify infected viral or tumor cells that have decreased MHC I surface expression and destroy these cells perforingranzymes. Secrete IFN-g that can enhance the phagocytic capability of macrophages and have cytoplasmic granules that have a similar mechanism to cytotoxic T-lymphocytes. NK-cells are activated by IL-12, IL-15, and type I interferons. Work synergistically with macrophages. Ref:- Review of Dermatology by Alikhan; pg num:-23 