GM-CSF Drives the Inflammatory Signature of CCR2+ Monocytes and Licenses Autoimmunity

In order to elucidate the role of GM-CSF for the development of EAE, mixed bone marrow chimeras (BMCs) were generated. Wt mice (F1 CD45.1+/CD45.2+) were lethally irradiated and reconstituted with a 1:1 mix of wt (CD45.1) and GM-CSFR-ko (CD45.2) BM. This setting allowed us to analyze wt vs. GM-CSFR-ko cells in the same animal. Two months after reconstitution, BMCs were subcutaneously immunized with MOG35-55/CFA. At the onset of disease, a subset of myeloid cells (wt-CD45.1 and GM-CSFRko-CD45.2) was sorted from the inflamed CNS using an ARIA Sorter (BD): Inflammatory DCs (CD45hi CD11b+, MHCII+, CD11c+, Ly6C+). Subsequently, RNA was prepared from the sorted cells (wt vs. GM-CSFR-ko) in order to perform gene expression profiling by next generation sequencing.