CD4 and infection: Upon primary infection with wildtype (Lm WT) and ovalbumin-expressing Lm (Lm OVA), pathogen control was significantly improved in CD4-Cre A20fl/fl mice in spleen (Fig. 1b,c) and liver (data not shown) at day 7 p.i. Up to day 50 p.i., Lm WT and Lm OVA were eliminated from spleens of both mouse strains.