Fig. 1.

MAIT cells are major contributors to cytokine production in response to fixed GAS or GAS supernatant. (A) Frequency of Vα7.2⁺CD161⁺ MAIT cells among total CD3⁺ cells and among CD3⁺ IFNγ⁺ or CD3⁺ TNF⁺ cells after 24 h stimulation of PBMCs with fixed GAS 2006 or GAS 2006 supernatant assessed by flow cytometry. (B and C) Kinetics of cytokine production after stimulation of PBMCs with GAS, presented as frequency of IFNγ⁺ or TNF⁺ cells among (B) total CD3⁺ cells or (C) MAIT cells assessed by flow cytometry. Media control yielded less than 1.5% IFNγ⁺ and 3% TNF⁺ cells at any time. (D) Frequencies IFNγ⁺ or TNF⁺ MAIT cells after 24 h stimulation with fixed GAS strains 2006 and 5448. (E) Frequency of CD69⁺ MAIT cells after stimulation with E. coli, GAS 2006, and GAS 5448. Data are presented as mean frequencies from (A and D) 6, (E) 7, or (B and C) 4 donors ± SD.