CSF2 and infection: This signaling pathway is activated by the growth factor GM-CSF, and we found its receptor, the Csf2rb gene, upregulated in both organs post-secondary infection, but also in every bone marrow subset at 24h post-PCA2 infection, and in the in the Multi-Lin-2, IG2 and MDP from bone marrow and the spleen of 7-day PCA2-infected mice (Figure 7D), indicating that these progenitors are better prepared to respond to GM-CSF.