FOS and infection: In line with this, all CD4+ T cell clusters from LCMV Cl13 infection displayed notable increases in their expression of certain intracellular signaling phosphatases and kinases, such as Dusp1, Dups2, and Pim1, as well in their expression of several genes encoding various TFs, including Jund, JunB, Fos, Klf2, and Bhlhe40 (Figure 4I).