CD8A and influenza: However, inactivated influenza vaccines provide only a weak stimulus to CD8+ T cell memory and translate to the poor induced GrB response to influenza vaccination and breakthrough LCII in vaccinated older adults that we have observed in multiple studies (McElhaney et al., 2001; McElhaney et al., 2006; McElhaney et al., 2009; Shahid et al., 2010).