β6 KO mice treated with TGF-β1 had increased numbers of CD11c+CD11b- macrophages (Fig 7C, quantification Fig 7D), partially reversing the CD11c+CD11b+ phenotype, and were no longer protected from influenza infection (Fig 7E) suggesting that the loss of β6-mediated TGF-β1activation is important for both protection and the ‘activated’ macrophage phenotype. This evidence concerns the gene ITGAX and influenza.