N/A (innate, non-antigen-specific NK-cell cytotoxicity)

Class

Allogeneic high-activity natural killer (NK) cell adoptive immunotherapy ("HANK" cell)

Pathway

MHC-independent NK-cell-mediated tumor cytotoxicity

Natural killer (NK) cells are white blood cells of the innate immune system that can recognize and kill abnormal cells, such as tumor cells, without requiring prior sensitization to a specific antigen. This distinguishes them from T cells, which need to recognize a particular protein fragment presented on a matched cellular marker called MHC (major histocompatibility complex). NK cells instead integrate signals from a balance of activating and inhibitory receptors on the target cell surface, allowing them to detect cells that have lost or altered their normal MHC display, a strategy often summarized as "missing-self" recognition. This MHC-independence is therapeutically attractive because it allows NK cells collected from a healthy donor (allogeneic) to be expanded, activated to a high state of cytotoxic readiness, and infused into a different, unmatched patient without the extensive genetic matching required for T-cell products, and generally without triggering the graft-versus-host disease associated with mismatched T cells. This mechanism is relevant across cancer types, including hematologic malignancies and solid tumors, where tumor cells frequently downregulate MHC molecules to evade T-cell surveillance, inadvertently rendering them more visible to NK-cell attack. Allogeneic NK cell therapies aim to provide an accessible, "off-the-shelf" cytotoxic effector population for use in these settings.