CD8A and infection: Representative examples of CD107 expression on CD3- lung NK cells in uninfected controls and chickens infected with tyTR05 and tyEng91 again show that CD107 is only expressed at CD3- cell that do not express CD8α (Fig. 8A).After infection with tyTR05, the percentage of activated NK cells in the lung decreased dramatically from 7.7 ± 0.5% in uninfected controls compared to 3.6 ± 0.7% at 8 hpi (p < 0.05).