What is the Difference Between NK Cells and NKT Cells?

Natural killer (NK) cells and natural killer T (NKT) cells are both subsets of lymphocytes that play important roles in the immune system, particularly in the control of tumors and infections. However, they have distinct properties and functions:

1. Origin and development: NK cells are part of the innate immune system, while NKT cells share characteristics of both innate and adaptive immunity. Most NKT cells are CD1d-restricted and develop within the thymus, arising from the same common lymphoid precursor pool as conventional T cells.
2. Receptors: NK cells express an array of receptors, including inhibitory, activating, adhesion, and cytokine receptors, that enable them to detect their cellular targets while sparing normal cells.
3. Functions: Both NK and NKT cells are dynamically involved in immune responses to cancer, exhibiting effector properties in the early stages of tumor development. However, in the later stages, NK cells become senescent, while NKT cells (excluding invariant NKT, iNKT cells) are exhausted in advanced cancers. iNKT cells develop increases in activation and effector function within the breast tumor microenvironment.
4. Immunotherapy: Targeting NK and NKT cells in cancer immunotherapy has become an area of significant interest, as they represent promising players in antitumor immunotherapy.

In summary, NK cells and NKT cells are distinct subsets of lymphocytes with unique properties and functions in the immune system. While they share some similarities, their differences make them important targets for specific immunotherapies in cancer treatment.

Comparative Table: NK Cells vs NKT Cells

Here is a table summarizing the differences between natural killer (NK) cells and natural killer T (NKT) cells:

NK cells are large granular lymphocytes, while NKT cells are a type of T cell that share morphological and functional characteristics with both T cells and NK cells. NKT cells are classified into two groups, Type I and Type II, based on differences in T cell receptor (TCR) usage. Both NK and NKT cells are innate cytotoxic lymphoid cells that produce inflammatory cytokines.