Clone mar1 5a3

Splenic naïve CD4⁺ T cells were obtained by the negative selection using the Mojo Sort Mouse CD4 T Cell Isolation Kit (Biolegend #480006) and positive selection using CD62L MicroBeads, mouse (Miltenyi Biotec #130-049-701). Naïve CD4⁺ T cells were plated onto 24-well tissue culture plates (Costar #3526) pre-coated with 1μg/ml Anti-mouse TCRβ (clone H57-597, Biolegend #109255, Lot#B312356) with 1μg/ml anti-CD28 antibody (clone 37.51, BioLegend #102116, Lot#B346685). Th1 cell cultures contained 15 ng/ml IL-2 (Peprotech #212-12, Lot#067108), 10 ng/ml recombinant mouse IL-12 (WAKO #095-05331, Lot#SAQ1865) and 1μg/ml anti-IL-4 antibody (Biolegend #504122, Lot#B336348). Recombinant mouse IFNβ (Biolegend #581302, Lot#B229335) were dissolved in PBS supplemented with 3% BSA and treated with 100U/ml. IFNAR neutralizing antibody (clone MAR1-5A3, Biolegend #127322, Lot#B163670) was treated with 10μg/ml.

PPARα agonist WY14643 was purchased from Cayman Chemical. For in vitro work PPARα agonist fenofibrate, PPARδ agonist GW501516, and PPARγ agonist rosiglitazone were purchased from Sigma-Aldrich. The polyclonal antibody against MHV68 has been previously described (36 (link)) and was generously provided by the Virgin lab. The antibody against IFNAR was purchased from Biolegend (clone MAR1-5A3, Biolegend #127312). The isotype control, Mouse IgG1, κ−isotype, was also purchased from Biolegend (clone MOPC-21, Biolegend number 400112).

For type I interferon blocking assays, human IFN‐β blocking antibody (Clone AF814; R&D) and its corresponding isotype (Goat IgG, R&D Systems) were used at a concentration of 0.2 µg/ml. Anti‐Interferon‐α/β Receptor Chain 1 Antibody (IFNAR1) (clone MAR1‐5A3; Biolegend, CA) and its corresponding isotype (Mouse IgG2a, clone GC270; Millipore) were used at 0.1 µg/ml. Where indicated, these reagents were added simultaneously with BO‐110 to the culture media.