What is a MAIT cell?

Mucosal associated invariant T cells (MAIT cells) make up a subset of T cells in the immune system that display innate, effector-like qualities. In humans, MAIT cells are found in the blood, liver, lungs, and mucosa, defending against microbial activity and infection.

Where do MAIT cells develop?

Mucosal-associated invariant T (MAIT) cells develop in the thymus and migrate into the periphery to become the largest antigen-specific αβ T-cell population in the human immune system.

Are MAIT cells CD4 or CD8?

Human MAIT cells predominantly express the CD8α coreceptor (CD8+), with a smaller subset lacking both CD4 and CD8 (double-negative, DN).

Do MAIT cells express CD3?

In humans, the frequency of MAIT cells is high in peripheral blood, and these cells constitute approximately 5% of circulating CD3+ cells. Their abundance in tissues and rapid activation following stimulation have led to great interest in their function in various types of immune diseases.

Do mice have MAIT cells?

In contrast to humans, however, MAIT cells are rarer in mice where they typically form <1% of all T cells, although in some tissues, such as lung, lamina propria and lymph node, they can constitute up to 5% of T cells12. Thus microbial exposure may be an important factor in dictating mature MAIT cell frequencies.

What do MAIT cells do?

As a specific population of innate-like lymphoid cells, MAIT cells are involved in early immunity against infection in peripheral tissue, with a more rapid response to pathogens and shorter time to effector function in vivo than conventional MHC-restricted T cells in infectious disease (63).

What do natural killer T cells do?

NK cells are part of the innate immune system, as they effect rapid killing and cytokine responses without the need for extensive cell division or differentiation. By contrast, conventional T cells are, together with B cells, the prototypic cell types of adaptive immunity.

What do gamma delta T cells recognize?

Gamma delta T cells (γδ T cells) are T cells that have a distinctive T-cell receptor (TCR) on their surface. Furthermore, γδ T cells are believed to have a prominent role in recognition of lipid antigens. They are of an invariant nature and may be triggered by alarm signals, such as heat shock proteins (HSP).

Do NKT cells express CD8?

An examination of NKT cell subsets in CD1d−/− mice revealed the CD1d-independent NKT cell subset; approximately 50% of the cells therein express CD816. This CD8-expressing CD1d-independent NKT cell subset has been referred to as “CD8+NKT cells” in some previous studies17,18,19.

How are MAIT cells activated?

MAIT cells can be activated in response to TCR ligation by riboflavin intermediates presented on MR1, under co-stimulatory signals from specific cytokines or toll-like receptors (TLR) (22).

Are NK cells and killer T cells the same?

NK cells differ from natural killer T cells (NKTs) phenotypically, by origin and by respective effector functions; often, NKT cell activity promotes NK cell activity by secreting interferon gamma.

What is the difference between natural killer cells and natural killer T cells?