Differential location of NKT and MAIT cells within lymphoid tissue

Darryl N Johnson,Phillip K Darcy,Jeffrey Y W Mak,James Mccluskey,Zheng Ruan,Lauren E Holz,Sapna Devi,David P Fairlie,Dale I Godfrey,Paul A Beavis,Emma V Petley,William R Heath,Adam P Uldrich,Scott N Mueller,Jyh Liang Hor

doi:10.1038/s41598-022-07704-4

Abstract

Natural Killer T (NKT) cells and Mucosal-Associated Invariant T (MAIT) cells are innate-like T cells that express semi-invariant αβ T cell receptors (TCRs) through which they recognise CD1d and MR1 molecules, respectively, in complex with specific ligands. These cells play important roles in health and disease in many organs, but their precise intra-organ location is not well established. Here, using CD1d and MR1 tetramer staining techniques, we describe the precise location of NKT and MAIT cells in lymphoid and peripheral organs. Within the thymus, NKT cells were concentrated in the medullary side of the corticomedullary junction. In spleen and lymph nodes, NKT cells were mainly localised within T cell zones, although following in vivo activation with the potent NKT-cell ligand α-GalCer, they expanded throughout the spleen. MAIT cells were clearly detectable in Vα19 TCR transgenic mice and were rare but detectable in lymphoid tissue of non-transgenic mice. In contrast to NKT cells, MAIT cells were more closely associated with the B cell zone and red pulp of the spleen. Accordingly, we have provided an extensive analysis of the in situ localisation of NKT and MAIT cells and suggest differences between the intra-organ location of these two cell types.

Highlights

Natural Killer T (NKT) and Mucosal-Associated Invariant T (MAIT) cells are two distinct classes of unconventional αβ T cells that recognise non-peptide antigens in complex with MHC class-I-like molecules
Voxel plots of the three groups indicated a clear association within BALB/c wild type (WT) sections of voxels stained with CD1dα-GalCer and TCRβ (Supplementary Fig. S1c)
They demonstrate the need to co-stain with T cell-specific markers such as TCRβ or CD3 and include negative controls for stain and tissue to best eliminate, albeit rare, non-NKT cell staining from analysis

Summary

Introduction

Natural Killer T (NKT) and Mucosal-Associated Invariant T (MAIT) cells are two distinct classes of unconventional αβ T cells that recognise non-peptide antigens in complex with MHC class-I-like molecules. CD1d-α-GalCer tetramer staining is the best way to accurately identify NKT cells and has been used with immunohistology to detect endogenous NKT cells in Vα14 TCR transgenic mice where NKT cells are highly a bundant[16]. This approach has been used to detect endogenous NKT cells in thymus, spleen, lymph nodes and adipose tissue[17–20]. In the case of MAIT cells, immunohistological staining for CD3, CD8, Vα7.2, CD161 and/or IL-18R has been used to study MAIT cells in human liver21–25, intestine22,26–29, pancreas30, brain[31–33] and lymph nodes[22] in either heathy or diseased states These surrogate markers are not limited to MAIT cells[5], so it is difficult to know if the cells detected were MAIT or MAIT-like cells. The location of MAIT cells, defined by MR1-5-OP-RU tetramer, in other tissues remains unknown

Methods

Results

Conclusion