To address the role of MZB cells in the production of IgM antibodies in atherosclerosis, we created a new atherosclerotic mouse model with No MZB cells from birth: Ldlr−/−; Cd79aCre/+; RBPflox/flox (No MZB) and Ldlr−/−; Cd79a+/+; RBPflox/flox (WT; Figure 4A). Here, CD40LG is linked to atherosclerosis.