Restitution of superoxide generation in autosomal cytochrome-negative chronic granulomatous disease (A22⁰ CGD)-derived B lymphocyte cell lines by transfection with p22^phox cDNA

The respiratory burst oxidase of phagocytes and B lymphocytes is a multicomponent enzyme that catalyzes the one-electron reduction of oxygen by NADPH. It is responsible for the O₂^- production that occurs when these cells are exposed to phorbol 12-myristate 13-acetate or physiologic stimuli, such as phagocytosis in phagocytes or cross-linking of surface immunoglobulin in B lymphocytes. The activity of this enzyme is greatly diminished or absent in patients with chronic granulomatous disease (CGD), an inherited disorder characterized by a severe defect in host defense against bacteria and fungi. In every CGD patient studied so far, an abnormality has been found in a gene encoding one of the four components of the respiratory burst oxidase: the membrane proteins p22^phox or gp91^phox which together form the cytochrome b558 protein, or the cytosolic proteins p47^phox or p67^phox. Autosomal recessive cytochrome-negative CGD (A22⁰ CGD) is associated with mutations in the gene coding for p22^phox. We report here that the capacity for O₂^- production and cytochrome b558 protein expression were restored to Epstein-Barr virus-transformed B lymphocytes from two A22⁰ CGD patients by transfection with an expression plasmid containing a p22^phox cDNA. No detectable O₂^- was generated by untransfected p22^phox-deficient lymphocytes. The genetic reconstitution of the respiratory burst in A22⁰ CGD B lymphocytes by transfer of the wild-type p22^phox cDNA represents a further step towards somatic gene therapy for this subgroup of A22⁰ CGD. This system will also be useful for expression of genetically engineered mutant p22^phox proteins in intact cells, facilitating the structure-function analysis of cytochrome b558.