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What is the difference among three atypical T cells: NKT MAIT and γδT?
What is the difference among three atypical T cells: NKT MAIT and γδT? This article will introduce some knowledge about three atypical T cells: NKT, MAIT and γδT?
Human and mouse non-classical T cells (Reference 2)
Natural killer T (NKT) cells, Mucosal Associated Invariant T (MAIT) cells and γδ T cells belong to natural lymphocytes with effector functions, atypical T cells, and antigen recognition is not subject to MHC I and II. Molecular restriction.
In terms of anti-tumor response, NKT cells play a prominent role.
NKT cells are usually divided into type I and type II; type I NK T cells are called semi-invariant NKT cells (iNKT) because they express the typical semi-invariant T cell receptor (TCR), while type II NKT Cells have different TCR banks. Both type I and type II NKT cells can recognize the glycolipid antigen on the CD1d molecule, but their roles in tumor immunity are significantly different. The abundance of type I NKT in mouse T cells is about 1%, and about 0.1% in humans.
NKT cell thymus development process (Reference 2)
Type 1 NKT recognizes the tumor lipid antigens (GD3, GM3, etc.) presented by CD1d on the surface of APC through TCR, thereby activating its anti-tumor immunity and directly killing tumor cells. In addition, NKT cells can also participate in the activation of effector T cells and eliminate CD1d-expressing suppressive immune cells.
NKT clinical research
γδ T cells
γδT lacks the expression of CD4 and CD8, and its abundance in circulation and lymph nodes is about 0.5-16%, of which Vγ9+Vδ2+ accounts for the highest proportion and can respond to small phosphorylated metabolite antigens.
For more γδ cell content, please click to read γδT cell basic biology, cell therapy development dilemma and progress
MAIT cells belong to another discrete atypical T cell subgroup, which is characterized by a limited TCR pool.
Compared with NKT cells, MAIT cells are more abundant in humans. It expresses the invariant α chain (Vα7.2-Jα33) and a limited type of β chain (human: Vβ2 or Vβ13), and recognizes the vitamin B metabolite antigen presented on the MHC-I related molecule MR1.
The physiological and pathological functions of MAIT are not very clear. It is known that the vitamin B metabolite antigen produced by bacteria and yeast can activate MAIT cells through MR1-TCR.
MAIT cell thymus development (Reference 2)
The physiological and pathological functions of MAIT are not very clear. It is known that vitamin B metabolite antigens produced by bacteria, yeast, viruses, etc., can activate MAIT cells through MR1-TCR to release granzyme B, perforin, IFN-γ, TNF-α kills infected cells.
MAIT anti-infection (reference 4)
- In the past two years, NKT has attracted the attention of scientific research and industry. It has begun to conduct research and development including bispecific antibodies and cell therapy.
- MAIT is more in-depth in infectious disease research. In tumor research, can MR1 present tumor antigens? Whether there are tumor cells that specifically express MR1 and so on to find opportunities for tumor immunity.
- The research of γδT is more in-depth, but because of the dynamic nature of TCR and the low affinity, there are not many breakthroughs in clinical use.
(source:internet, reference only)