Figure 1From: Peripheral tolerance induced by apoptotic cells and PD-1+ CD8 T cellsPD-1 is essential for tolerance induced by apoptotic cells. TNP-apoptotic cells were injected intravenously into PD-1 hetero- or homo- deficient mice. The mice were immunized with TNP (Filled bar) or preconditioned with apoptotic cells before immunization with TNP (open bar).Back to article page