CD4 and Autoimmunity: Anti-MPO autoimmunity is induced and to trigger glomerular injury, a subsequent sub-nephritogenic (does not cause glomerular injury when injected into unsensitized wild type mice) dose of sheep anti-mouse glomerular basement membrane (GBM) globulin is used to recruit neutrophils to glomerular capillaries where they degranulate, depositing MPO and triggering anti-MPO CD4+ effector T cell responses [36].