IgG autoantibodies against interleukin 1 alpha in sera of normal individuals.
A pool of human sera from healthy blood donors was found to interfere competitively with the binding of 125I-labelled human recombinant interleukin 1 alpha (rIL-1 alpha) to the murine T-cell line EL4. The interference was reversible at the cellular level, and direct binding of the ligand to serum factors was therefore investigated. After preincubation of [125I]rIL-1 alpha with pooled serum, the 125I activity eluted in two peaks from a Sephadex G-75 column. The first was located in the void volume. The second eluted together with monomer rIL-1 alpha. An almost complete displacement of the high molecular weight 125I fraction was achieved with an excess of unlabelled rIL-1 alpha but not with rIL-1 beta. The serum factors binding to [125I]rIL-1 alpha were located in the molecular weight range 100,000-200,000, judged by fractionation on a Sephacryl S-400 column, and the factors were bound to immobilized protein A. Furthermore, [125I]rIL-1 alpha preincubated with serum co-precipitated with a specific rabbit anti-human IgG antibody. Screening of 29 sera from normal individuals showed similar effects in three cases. We conclude that approximately 10% of normal human sera contains detectable IgG autoantibodies to IL-1 alpha.
Svenson
M
M
Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark.
Poulsen
L K
LK
Fomsgaard
A
A
Bendtzen
K
K
D000328:Adult; D000818:Animals; D001323:Autoantibodies / Q000032:analysis*; D001666:Binding Sites, Antibody; D002460:Cell Line; D002850:Chromatography, Gel; D006801:Humans; D007106:Immune Sera / Q000032:analysis*; D007074:Immunoglobulin G / Q000032:analysis* / Q000378:metabolism; D007375:Interleukin-1 / Q000037:antagonists & inhibitors / Q000276:immunology* / Q000378:metabolism; D051379:Mice; D008970:Molecular Weight
D001323:Autoantibodies; D007106:Immune Sera; D007074:Immunoglobulin G; D007375:Interleukin-1