title: Interleukin-1 receptor antagonist blocks chemokine production in the mixed lymphocyte reaction.
abstract: The mixed lymphocyte reaction (MLR) has previously been used to elucidate pathways of cytokine activation and T-lymphocyte proliferation and is regarded as a model that simulates responses in allograft rejection. Studies have indicated that interleukin-1 (IL-1), a potent inflammatory cytokine, may have an important activating role in the MLR response. The discovery of a naturally occurring IL-1 receptor antagonist protein (IRAP) has renewed interest in control of IL-1--dependent responses both in vitro and in vivo. MLR cultures were used to study the role of IL-1 and IRAP in the regulation of subsequent cytokines during a T-lymphocyte-mediated alloantigen response. The temporal expression of IL-1 and IRAP during 5-day one-way MLR assays suggested antagonistic production of the two cytokines. IL-1 was produced early in the response, peaking at 4 hours through day 2, subsequently declining to near-background levels on day 5 of culture. In contrast, production of IRAP was delayed until day 2, steadily increased on days 3 and 4, and peaked on day 5 of culture, which correlated with the declining levels of IL-1. The addition of graded doses of IRAP (25 to 1,000 ng/mL) to MLR cultures decreased IL-1 production but had no effect on T-lymphocyte proliferative response. In addition, IRAP had little effect on the production of either IL-2 or tumor necrosis factor. The addition of 25 ng/mL of IRAP to MLR assays showed significantly decreased levels of two potent chemotactic cytokines, IL-8 and macrophage inflammatory protein-1 alpha (MIP-1 alpha), at peak chemokine production on day 5 of culture. The levels of IL-8 and MIP-1 alpha could be restored by the addition of IL-1 to the IRAP-treated cultures. IL-8 and MIP-1 alpha represent the two different families of chemotactic cytokines, C-X-C (IL-8) and C-C (MIP-1 alpha), and potentially play important roles in the recruitment of leukocytes to a site of immune allogeneic response. These studies indicate that regulation of IL-1 by IRAP does not significantly reduce T-lymphocyte activation but can regulate the production of chemokines involved in leukocyte recruitment.
authors.affiliation: Department of Pathology, University of Michigan Medical School, Ann Arbor 48109-0602.
authors.forename: N W
authors.initials: NW
authors.lastname: Lukacs
authors.forename: S L
authors.initials: SL
authors.lastname: Kunkel
authors.forename: M D
authors.initials: MD
authors.lastname: Burdick
authors.forename: P M
authors.initials: PM
authors.lastname: Lincoln
authors.forename: R M
authors.initials: RM
authors.lastname: Strieter
mesh_terms: D002478:Cells, Cultured; D054407:Chemokine CCL4; D016207:Cytokines / Q000032:analysis / Q000096:biosynthesis; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D053590:Interleukin 1 Receptor Antagonist Protein; D007375:Interleukin-1 / Q000032:analysis / Q000096:biosynthesis*; D016209:Interleukin-8 / Q000032:analysis / Q000096:biosynthesis; D007700:Kinetics; D007959:Lymphocyte Culture Test, Mixed; D008214:Lymphocytes / Q000187:drug effects / Q000276:immunology*; D019402:Macrophage Inflammatory Proteins; D015846:Monokines / Q000032:analysis / Q000096:biosynthesis; D017472:Receptors, Interleukin-1 / Q000037:antagonists & inhibitors*; D012795:Sialoglycoproteins / Q000032:analysis / Q000494:pharmacology*; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis / Q000096:biosynthesis
chemical_list: D054407:Chemokine CCL4; D016207:Cytokines; C507763:IL1RN protein, human; D053590:Interleukin 1 Receptor Antagonist Protein; D007375:Interleukin-1; D016209:Interleukin-8; D019402:Macrophage Inflammatory Proteins; D015846:Monokines; D017472:Receptors, Interleukin-1; D012795:Sialoglycoproteins; D014409:Tumor Necrosis Factor-alpha