mice that lack Aire, demonstrating it as an important regulator of XCL1 production. Naive CD8+ T cells are prepared when tumors form by cross-presentation via XCR1+ DCs and as a result will require a lower threshold to respond to antigen. Memory CD8+ T lymphocytes (mCTLs) are activated first after infection and then are signaled by CXCR3, IL-12, and CXCL9 by other XCR1+ DCs. In order to make a powerful secondary infection response, cytokine and chemokine signaling between XCR1+ DCs and NK cells must occur. References External links Further reading External links Cytokines Cell biology Receptors Integral membrane proteins