ARG1 and infection: As the infection progresses, the macrophages exhibit an alternatively activated phenotype with the ability to block lymphocyte proliferative response and express high levels of chitinase-like 3 (Chil3) type 1 (Ym1) and arginase 1 (Arg1), likewise programmed death-ligands 1 and 2 (PD-L1 and PD-L2) [5,6].