Beyond the Immune System: The Immunotrophic Role of T Cells in Organ Generation and Regeneration

Immunotrophism is herein defined as the role played by T cells in promoting organ generation and regeneration. Evidence over a variety of organ systems is presented to show that T cells and their lymphokines can affect various growth phenomena. Perhaps the clearest example to date is the placenta, which is recognized as an allogeneic entity by the maternal immune system. We postulate that changes in expression of major histocompatibility antigens serve as a signal for this effect, which results in T cell activation of target tissue expansion and, simultaneously, immune suppression. These concepts are then applied to a scenario for the evaluation of the immune response.