Tumor and allogeneic host cells recognized by donor T cells and NK cells

This entry does not describe a single molecular target but rather a complex cellular interaction occurring in the context of allogeneic hematopoietic stem cell transplantation (HSCT) and adoptive immunotherapy. It refers to the recipient's (host) normal tissues and malignant cells that are identified as foreign by the donor's immune system, specifically T cells and Natural Killer (NK) cells. The recognition is primarily mediated by the interaction between donor immune receptors (such as T-cell receptors and KIRs) and host antigens, including Major Histocompatibility Complex (MHC/HLA) molecules and minor histocompatibility antigens. In clinical practice, the goal of therapeutic intervention is to balance the Graft-versus-Tumor (GvT) effect, where donor cells eradicate residual cancer, with the prevention of Graft-versus-Host Disease (GvHD), where donor cells attack healthy host organs. Drugs interacting with this 'target' system include immunosuppressants like calcineurin inhibitors and T-cell depleting antibodies like antithymocyte globulin. Because this represents a multi-cellular biological process rather than a discrete protein or gene, it is classified as an incorrect molecular target designation in a traditional pharmacological sense.

Other names

Allogeneic host cellsGraft-versus-host disease target cellsGraft-versus-tumor target cells

Immunosuppressive agents and T-cell depleting antibodies modulate the activity of donor-derived T cells and NK cells to prevent them from attacking host tissues (GvHD) while ideally preserving their ability to eliminate residual tumor cells (GvL).