CASP3 and infection: However, at the 8th week post-infection, PD-1, PD-L1, Bcl-2, Caspase-3 and TCR in the spleen of this group were upregulated, and the values of total IgG, IgG1 and IgG2a were all low, indicating that this might be due to immunosuppression and increased T cell exhaustion resulting in the highest parasite load.