Docosahexaenoic acid (DHA) was obtained from Cayman Chemical (Ann Harbor, MI, USA), RPMI and DMEM media and fetal bovine serum (FBS) from Invitrogen (Carlsbad, CA, USA), and mouse interleukin 4 (IL-4) from Sigma Chemical (St Louis, MO, USA). Mouse diets were purchased from DYETS, Inc. (Bethlehem, PA). For the ω−6 diet, 30% of energy (134g/kg) was provided by corn oil, and the ω−6 to ω−3 ratio was 18:1. For the ω−3 diet 30% of energy was provided by menhaden oil (134g/kg) and the ω−6 to ω−3 ratio was 1:8 as previously described [11 (link)].