Furthermore, depletion of CD4+ T cells prior to influenza challenge results in a dramatic drop of Ab titres (Eichelberger et al., 1991), accompanied by only a small delay in virus elimination (Allan et al., 1990), driven by the remaining CD8+ T cell response (Topham et al., 1996; Belz et al., 2002). Here, CD8A is linked to influenza.