CONSTITUTIVE EXPRESSION OF PORE-FORMING PROTEIN IN PERIPHERAL-BLOOD GAMMA-DELTA-T-CELLS - IMPLICATION FOR THEIR CYTOTOXIC ROLE INVIVO

The cytotoxic activity and pore-forming protein (PFP) expression of human peripheral blood (PB) γ/δ T cells were examined. Fresh γ/δ T cells isolated from PB lymphocytes by fluorescenceactivated cell sorting exhibited a substantial natural killer-like cytotoxic activity against K562 target cells and had a high cytotoxic potential triggered by anti-CD3 monoclonal antibody (mAb) against P815 target cells bearing Fc γR. Immunocytochemical staining with an anti-PFP mAb revealed that virtually all PB γ/δ T cells are granular lymphocytes with abundant PFP in their cytoplasmic granules. Constitutive expression of PFP in PB 'y/6 T cells was also demonstrated by Northern blot analysis. These observations support the proposed role ofγ/δ T cells in cytolysic immune surveillance in vivo. © 1990, Rockefeller University Press., All rights reserved.