High levels of MAIT cell activation is evident in the
gastrointestinal tissue of patients with IN-COL
There was no significant difference between IN-COL and IN-NAE groups in
regard to the MAIT cell count in GMNC (Figure 2ci). IN-COL was
associated with a significantly higher proportion of
HLA-DR+CD38+ activated MAIT cells
(20% of MAIT cells) compared with the IN-NAE group (2%;
p>0.01; Figure 2cii). IN-COL was also associated with a
greater proportion of granzyme B+ MAIT cells (19% vs
0% of MAIT cells; p<0.05; Figure 2ciii). These changes did
not occur in UC. We further confirmed activation of MAIT cells in the
tissue by using fluorescently conjugated tetramers to the MAIT TCR
ligand (MR1-OP5) and confirmed
CD161+tetramer+ T cells were
activated in IN-COL (19%
HLA-DR+CD38+) but not IN-NAE (0.5%;
Figure 2d).
Finally, we confirmed that MAIT cell activation was greater in the
gastrointestinal tract than in the peripheral blood by studying paired
GMNC and PBMC in IN-COL (N=3) and IN-NAE (N=3). While patients with
IN-COL had marginally higher MAIT cell activation measured in PBMCs
compared with the IN-NAE group, this difference was more marked in the
GMNC samples of 2/3 patients (Figure 2e).