ESTABLISHMENT OF A HUMAN T-CELL LINE WITH DEFICIENT SURFACE EXPRESSION OF GLYCOSYLPHOSPHATIDYLINOSITOL (GPI)-ANCHORED PROTEINS FROM A PATIENT WITH PAROXYSMAL-NOCTURNAL HEMOGLOBINURIA

A novel interleukin-2 dependent T-cell line, PMT-2Y, was established f rom the peripheral blood of a patient with paroxysmal nocturnal haemog lobinuria (PNH) by human T lymphotropic virus type I (HTLV-I)-mediated transformation. PMT-2Y cells are positive for CD2, CD3, CD4, CD25, T cell receptor alpha beta and HLA-DR, but negative for CD1, CD7, CD8, C D19 and CD20, indicating that the clone belongs to a helper/inducer su bset of T cells. PMT-2Y cells have the monoclonal integration of HTLV- I proviral DNA, suggesting that they derived from a single clone. More over, they lack surface expression of complement regulatory proteins s uch as DAF (CD55) and CD59, that are the most important glycosylphosph atidylinositol (GPI)-anchored membrane proteins defective in haemopoie tic cells of patients with PNH. Northern blot analysis, however, revea led the production of normal levels of DAF mRNAs. Thus, PMT-2Y is deri ved from a PNH T cell clone and may be a useful model to study PNH.