Immune reactions with cytotoxic activity to "self" in natural surveillance of aberrant cells.

Cytotoxic autoreactive lymphoid cells have been demonstrated to be a normal immunologic component in both normal and tumor-bearing organisms. The cells have a high antineoplastic potential. They are cytotoxic in vitro to non-immunogenic tumor cells, and a high in vivo activity of such cells may be positively correlated to in vivo regression of tumors. It is suggested that the cytotoxic activity of cytotoxic autoreactive cells reflects a natural mechanism to removal of all types of aberrant cells of which malignant cells are only a subset. It is further deduced that such mechanisms must be independent of cell surface neoantigens, and that cytotoxic autoreactive mechanisms with high probability therefore also are efficient against spontaneous malignant tumors.