PSMB9 and infection: Upon infection with pathogens, such as influenza virus, Lymphocytic Choriomeningitis Virus (LCMV), and Listeria monocytogenes, pronounced differences in the immunodominance hierarchies of induced responses were observed in all single or double (LMP7/β5i and LMP2/β1i or MECL-1/β2i) gene-deficient strains [37,47,48,49].