LAG3 and Autoimmunity: Moreover, whereas genetic deletion or blockade of inhibitory immune checkpoint LAG-3 (expressed on exhausted T cells infiltrating the tumor and which is also not involved in T cells priming) exacerbates type 1 diabetes in non-obese diabetic mice, LAG-3 deficiency itself does not lead to autoimmunity in non-autoimmune-prone mouse strains (129).