CD8A and Autoimmunity: Upon activation, its expression is elevated on T cells to prevent autoimmunity in concert with PD-130 and is also one of the hallmarks of exhausted CD8+ T cells.31,32 By selectively recognizing stable complexes of peptide and MHC class II (pMHCII), LAG-3 inhibits the activity and expansion of CD4+ effector T cells and antigen-specific CD8+ T cells33–37 (Fig. 2).