CD47 and viral infectious disease: During chronic Cl-13 LCMV infection, Cd47−/− mice had significantly higher virus titers in serum than WT mice on days 8 (1.9-fold more in Cd47−/− than WT) and 15 (2.2-fold more in Cd47−/− than WT), suggesting viral infection progressed relatively faster in Cd47−/− mice (Figures 5A,B).