Flow cytometry of CD59 on JY5 cells transfected with mutant PIG-A cDNA and on B-lymphoblastoid cell lines established from patient J19. (A) The PIG-A–deficient human lymphoblastoid cell line JY5 transfected with PIG-A cDNA bearing mutation 1. (B) The PIG-A–deficient human lymphoblastoid cell line JY5 transfected with PIG-A cDNA bearing mutation 2. (C) JY5 transfected with normal PIG-A cDNA. (D through F ) The completely deficient TK-14⁻, the partially deficient TK-1⁻ and the wild-type TK-4⁺–lymphoblastoid cell lines derived from this patient, respectively. Solid lines, anti-CD59; dotted lines, isotype-matched control monoclonal antibody.