Pooled immune serum (4.8 IU/ml, 0.5 ml/mouse intraperitoneally [i.p.]) was transferred to ERA virus-infected MALT1−/− mice at 10 dpi, which corresponds to the time point when MALT1+/+ mice normally start to produce VNA after infection with ERA virus (Fig. 8A). This evidence concerns the gene MALT1 and infection.