The role of B7-H1 in the connection of NK and T-cell immunity against tumor dormancy. Immunization by DA1-3b/CXCL10 cells activates NK cells and leads to expression of B7-H1. NK-associated B7-H1 activates T cells through an as-yet-unidentified counter-receptor (CoR). Activated T cells secrete cytokines such as interferon-γ to enhance NK activity, leading to destruction of dormant DA1-3b leukemia cells. These findings establish an important B7-H1 connection between innate and adaptive immunity.