A role for intracellular components of target cells in activation of the immunosurveillance network.

The role of cells of lymphoid and myeloid origin as effectors in the immunosurveillance network is based upon their recognition of surface structures on target cells. The work described here, however, has focused on an alternative class of target molecules, that is, soluble intracellular factors, as potential immunogens. Results from this study, which was aimed at a biochemical definition of the tumor immunoenvironment, demonstrate that the soluble intracellular contents of a tumor cell line are significantly more effective than the extracellular medium conditioned by the same cells in both stimulating the growth of a human T-lymphocyte line and inducing differentiation markers in a human myeloid leukemic cell line. A proposal is made for a restructuring of the way in which the immunosurveillance network is considered. Specifically, it is suggested that the soluble intracellular components of tumor cells may serve as immunogens in the immunosurveillance network. It is further proffered that an understanding of the physical and chemical states of molecules which under pathologic conditions become exposed to effector components of the immunosurveillance network will give rise to new immunotherapeutic venues.