A comparative study of the in vitro immunomodulatory activity of human intact immunoglobulin (7S IVIG), F(ab′) 2 fragments (5S IVIG) and Fc fragments. Evidence for post‐transcriptional IL‐2 modulation

During the past few decades intravenous immunoglobulin (IVIG) has been used successfully in the treatment of various immunoregulatory disorders. Treatment results have been attributed to immunomodulation mainly via Fc receptors or by anti-idiotypic antibodies to disease-causing autoantibodies. From the present study it is clearly evident that 7S IVIG (intact immunoglobulin) as well as 5S IVIG [F(ab')2 fragments] and Fc fragments have a potent immunomodulatory capacity. We demonstrate that mainly 7S IVIG inhibits alloantigen-induced T-cell proliferation and generation of cytotoxic T lymphocytes. Reduced interleukin-2 (IL-2) protein levels in culture supernatants of IVIG-supplemented mixed ly…