CHARACTERIZATION OF THE SUPEROXIDE-GENERATING SYSTEM IN HUMAN PERIPHERAL LYMPHOCYTES AND LYMPHOID-CELL LINES

In B lymphocytes, but not T lymphocytes, isolated from human periphera l blood, we detected the four protein components essential for ''the r espiratory burst'' by immunoblot analyses using peptide-directed antib odies. These are two membrane proteins, namely, 91- and 22-kDa subunit s of cytochrome b(558), and two cytosolic proteins with molecular mass es of 47 and 65 kDa. Like in neutrophils, cytochrome b(558) was expres sed on the cell surface of peripheral B lymphocytes. Mean amounts (n = 8) of the 91-, 22-, 47-, and 65-kDa proteins, respectively, in periph eral B lymphocytes calculated from intensity of the blots were 0.011+/ -0.003, 0.026+/-0.006, 0.179+/-0.022, and 0.039+/-0.013 relative to th ose in neutrophils on the basis of cell number. Epstein-Barr virus (EB V)-transformed cell lines derived from normal B lymphocytes and some B cell lines also possessed cytochrome b(558) and two cytosolic protein s. Isolated human peripheral B lymphocytes generated the superoxide an ion upon cross-linking of surface antigens such as IgM, IgD, IgG, HLA- DR, and CD19, EBV-transformants derived from normal peripheral B lymph ocytes and B lymphoid cell lines also generated the superoxide anion w hen stimulated with various antibodies against surface antigens. These results indicate that peripheral B lymphocytes have substantial amoun ts of a superoxide-generating system identical to that in phagocytes a nd that the system is stimulated to generate the superoxide anion by t he cross-linking of clonally expressed surface immunoglobulins or of c ertain surface antigens.