Inhibition of NKp46-induced NK cell activation by antibody-mediated triggering of CD161.

<p>PBMC were isolated and stimulated for three hours with the anti-NKp46 mAb 9E2 combined with the anti-CD161 mAb 191B8 or an isotype matched control antibody. The antibodies had been coupled to Fc-receptors on P815 cells. Activation of NK cells was assessed by monitoring CD107a expression on gated CD3^-CD56⁺ cells. (A) Representative dot-plots showing weaker down-regulation of NK cell activation by anti-CD161 triggering in NK cells from a CC carrier compared to cells from a TT individual. (B) Frequency of activated NK cells after stimulation with anti-NKp46 plus isotype control and anti-NKp46 plus anti-CD161. PBMC from nine individuals with CD161 TT and nine carriers of CC were studied. (C) Diminished capacity of CD161 from CC carriers to inhibit NKp46-induced NK cell activation. % Inhibition was calculated as follows: 100 - [(%CD107a⁺ NK cells after stimulation with NKp46-CD161 / % CD107a⁺ NK cells after stimulation with NKp46-isotype) x 100]; *p<0.05 (Unpaired t-test).