Truncated Thioredoxin Is a Mitogenic Cytokine for Resting Human Peripheral Blood Mononuclear Cells and Is Present in Human Plasma

摘要: Abstract Human thioredoxin (Trx) catalyzes intracellular disulfide reductions but has also co-cytokine activity with interleukins after leaderless secretion. A recombinant truncated form of the 80 N-terminal residues (Trx80) was purified to homogeneity. We discovered that Trx80 by itself is a potent mitogenic cytokine stimulating growth resting human peripheral blood mononuclear cells. No effect seen Trx, at 50–100 nm induced cell proliferation cells in serum-free synthetic medium, measured as [3H]thymidine incorporation 72 h, maximum being comparable 5 units/ml interleukin-2. lacked redox activity, CD spectra suggested secondary structure similar Trx. Reduced had anM r 25,000, indicating it dimer solution. developed two different sandwich enzyme-linked immunosorbent assays distinguish between full-length Trx and determined plasma levels donors. The varied from 2 175 ng/ml; comparison 16 55 ng/ml without correlation Trx80. In conclusion, naturally occurring novel for normal