Lymphocyte phenotypic markers

One lineage choice that occurs rather late in T-cell ontogeny is the development of NKT cells. NKT cells express markers of both NK cells and T lymphocytes. These include Ly49 family receptors NKl.l and TCR in mice. Mature NKT cells are CD44 CD69, a phenotype consistent with an activated cell. A hallmark of NKT cells is copious IL-4 and IFN-y secretion promptly upon TCR activation. Because of this property, NKT cells most Likely possess regulatory fimctions. They suppress multiple autoimmune phenomena, and in some cases, inhibit tumor metastases. Unlike conventional a 3 T cells that are selected by classical MHC class I and II, the vast majority of NKT cells are selected by the non-polymoiphic class I-like molecule, CD Id. 

The most obvious example of a cellular component of the immune system is the lymphocyte and includes all the various subtypes of T and B cells. As indicated previously, the fundamental distinction between T cells and B cells is based on the specific primary lymphoid organ in which the final stages of lymphopoiesis takes place. As described below, these cell types can also be distinguished based on their respective functions within the immune system as well as by phenotypic characteristics. For the purposes of this entry, a phenotype will be defined as a marker expressed on the surface of a cell which is genetically determined and which is frequently associated with the specific function of that... 

TABLE 3.2-3 Markers Used for Standard Lymphocyte Subset Phenotyping... 

---