The nuocyte is a cell of the innate immune system that plays an important role in type 2 immune responses that are induced in response to helminth worm infection or in conditions such as

asthma Asthma is a long-term inflammatory disease of the airways of the lungs. It is characterized by variable and recurring symptoms, reversible airflow obstruction, and easily triggered bronchospasms. Symptoms include episodes of wheezing, co ...

and

atopic Atopy is the tendency to produce an exaggerated immunoglobulin E (IgE) immune response to otherwise harmless substances in the environment. Allergic diseases are clinical manifestations of such inappropriate, atopic responses. Atopy may have a ...

disease. Nuocytes are amongst the first cells activated in type 2 immune responses and are thought to play important roles in activating and recruiting other cells types through their production of type 2

cytokine Cytokines are a broad and loose category of small proteins (~5–25 kDa) important in cell signaling. Cytokines are peptides and cannot cross the lipid bilayer of cells to enter the cytoplasm. Cytokines have been shown to be involved in autocrin ...

interleukin 4 The interleukin 4 (IL4, IL-4) is a cytokine that induces differentiation of naive helper T cells ( Th0 cells) to Th2 cells. Upon activation by IL-4, Th2 cells subsequently produce additional IL-4 in a positive feedback loop. IL-4 ...

, 5 and 13. Nuocytes have been observed to proliferate in the presence of

interleukin 7 Interleukin 7 (IL-7) is a protein that in humans is encoded by the ''IL7'' gene. IL-7 is a hematopoietic growth factor secreted by stromal cells in the bone marrow and thymus. It is also produced by keratinocytes, dendritic cells, hepatocytes, ne ...

(IL-7) ''in vitro''. Nuocytes contribute to the expulsion of helminth worms and to the pathology of

colitis Colitis is swelling or inflammation of the large intestine ( colon). Colitis may be acute and self-limited or long-term. It broadly fits into the category of digestive diseases. In a medical context, the label ''colitis'' (without qualification ...

and allergic airways disease. The nuocyte was identified at the same time as several other immune cells that play similar roles in type 2 immunity. These include Natural Helper Cells (NHCs), Innate Helper 2 (Ih2) cells and multi-potent progenitor (MPP) type 2 cells. The exact relationship between these cell types remains contentious but all share a type-2-inducing phenotype. MPP type 2 cells appear to differ from the other populations in that they have a myeloid, rather than

lymphoid The lymphatic system, or lymphoid system, is an organ system in vertebrates that is part of the immune system, and complementary to the circulatory system. It consists of a large network of lymphatic vessels, lymph nodes, lymphatic or lymphoid o ...

, origin. Nuocytes have been shown to have a lymphoid origin and a developmental pathway that is dependent upon the transcription factor RORα and Notch signalling. Pro-T cell progenitors retain nuocyte developmental potential but, unlike T cells, the

thymus The thymus is a specialized primary lymphoid organ of the immune system. Within the thymus, thymus cell lymphocytes or ''T cells'' mature. T cells are critical to the adaptive immune system, where the body adapts to specific foreign invaders. ...

is dispensable for their development.

References

See also