Based on the strong inhibitory effect of GFHPD on CD4+ T-cell infiltration into the colonic compartment in AOM/DSS mice, we further quantified colonic expression of the immune checkpoints Pd-1 and Ctla4, as well as their respective ligands Pd-l1 and Cd80 or Cd86 (Figure 6a). Here, CTLA4 is linked to infectious otitis media.