CD200-dependent and nonCD200-dependant pathways of NK cell suppression by human IVIG
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Intravenous immunoglobulin (IVIG) has been used to suppress autoimmune and inflammatory disorders by a variety of mechanisms. Recently, the CD200 tolerance-promoting signal has been found to play a role in IVIG suppression of blood natural killer (NK) cells. Further, different types of IVIG have been reported to differ in this activity, and that has been related to efficacy (and inefficacy) of treatment of women with pregnancy failure. CD200 acts by binding to CD200 receptors (C200R). The objective of this study was to determine if CD200-dependent NK suppression by IVIG involved direct binding of IVIG-associated CD200 molecules to CD200R on NK cells.
Method of study
Peripheral Blood Lymphocytes isolated from human blood were used as a source of NK cells to lyse Cr51-labelled K562 target cells in vitro in 18 and 4 h assays, and three different types of IVIG were tested for suppressive activity in the presence or absence of specific monoclonal anti-huCD200. In some experiments, CD56+ NK cells were purified using anti-CD56 magnetic beads. Western blotting of IVIG using a specific anti-huCD200 antibody was done. Enzyme-Linked ImmunoSorbent Assays were used to measure cytokine production in NK assays.
Different IVIGs showed significant differences in potency in suppressing NK cytolytic activity in vitro (mg/ml for 60% suppression, Gammagard 4.1, Gamunex 14.1, Gamimmune 20.2). For CD200-dependent suppression, Gammagard was twice as potent as Gamimmune, but equivalent to Gamunex. The presence of suppression in 4 hour assays indicated stimulation of cytokine synthesis was unlikely to explain CD200-dependent suppression. Purification of NK cells led to loss of the CD200-dependent component. Western blotting confirmed that material reactive with anti-CD200 antibody was present in Immunoglobulin G (IgG) preparations, and at a lower level in human serum that contains IgG.
IVIGs are not all equipotent in suppressing NK cell cytolytic activity. CD200 associated with IVIG is an important component of suppression. CD200-dependent suppression appears to be mediated by a non-NK population that then acts on NK cells by direct contact rather than indirectly through release of immunosuppressive cytokines.
KeywordsIVIG CD200 NK cells Pregnancy immunology
Supported by peer review grants from Canadian Institutes of Health Research (CIHR)/Bayer/Haema Quebec Blood Partnership, and CIHR.
- 8.Wright GJ, Cherwinski H, Foster-Cuevas M, Brooke G, Puklavec MJ, Bigler M, Song Y, Jenmalm M, Gorman D, McClanahan T, Liu M-R, Brown MH, Sedgewick JD, Phillips JH, Barclay AN. Characterization of the CD200 receptor family in mice and humans and their interaction with CD200. J Immunol. 2003;171:3034–46.PubMedGoogle Scholar
- 12.Yamada H. Recurrent miscarriage, genetic/immunologic factor and immunoglobulin therapy. Am J Reprod Immunol. 2007;58:191.Google Scholar
- 13.Stassen M, Fondel S, Bopp T, Richter C, Muller C, Kubach J, Becker C, Knop J, Enk AH, Schmitt S, Jonuleit H. Human CD25+ regulatory T cells: two subsets defined by integrins α4β7 or α4β1 confer distinct suppressive properties on CD4+ T helper cells. Eur J Immunol. 2004;34:1303–11.PubMedCrossRefGoogle Scholar
- 15.Shalev I, Liu H, Koscik C, Bartczak A, Javadi M, Wong K, Maknojia A, He W, Liu MF, Diao J, Cattral M, Gommerman J, Clark DA, Phillips MJ, Gorczynski RM, Zhang L, Downey G, Grant D, Cybulsky MI, Levy GA. Targeted deletion of fgl2 leads to impaired regulatory T cell activity and development of autoimmune disease. J Immunol. 2008;180:249–60.PubMedGoogle Scholar