In contrast to wild-type littermates (CD4-Cre+/+ MALT1FL/FL), infection of T cell-specific MALT1−/− mice (CD4-Cretg/+ MALT1FL/FL) with ERA virus led to severe disease and death between 15 and 17 dpi (Fig. 9B), similarly to the phenotype observed in MALT1 full-knockout mice (Fig. 1). Here, CD4 is linked to infection.