Research results obtained over many years on helper and suppressor T-cell functions were reviewed as follows; the role of NK cells in immune responses, immunoregulation by killer molecules, involvement of CD86 (B70) and CD80 (B7) in immunotolerance, and attempts at the human application of immunotolerance by transplantation from the viewpoint of cellular immunology. Based on this latest knowledge, a new research strategy of clinical application enabling the withdrawal of immunosuppressors in patients with organ transplantation is expected.
