title: Essential role of NK cells in IgG therapy for experimental autoimmune encephalomyelitis.
abstract: Intravenous immunoglobulin has long been used in treating autoimmune diseases, although mechanisms remain uncertain. Activating Fcγ receptors are receptors of IgG and reported to be essential in intravenous immunoglobulin (IVIG) therapy. Therefore, we hypothesized natural killer (NK) cells, which express abundant activating Fcγ receptors, are the potential cellular target. In experimental autoimmune encephalomyelitis (EAE), we demonstrated that IgG suppressed disease development in intact, but not in NK cell depleted mice. Adoptive transfer of IgG-treated NK cell could protect mice against EAE, and suppressed interferon γ and interleukin 17 production. The percentage of CD4(+)Foxp3(+) regulatory T cells was significantly increased. The increase of regulatory T cells was also observed in IgG-treated EAE mice but not in NK cell depleted mice. In vitro experiments confirmed that IgG-treated NK cells enhanced regulatory T cell induction from naïve CD4(+) T cells. Interestingly, cells from draining lymph nodes produced more interleukin 2 after the adoptive transfer of IgG-treated NK cells. We neutralized interleukin 2 and the induction of CD4(+)Foxp3(+) T cells by IgG-treated NK cells was significantly reduced. To our knowledge, we identified for the first time the critical role of NK cells in the mechanism of IgG-induced induction of Treg cells in treatment of autoimmunity.
authors.affiliation: Department of Paediatrics and Adolescent Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China.
authors.forename: Wai Po
authors.initials: WP
authors.lastname: Chong
authors.forename: Man To
authors.initials: MT
authors.lastname: Ling
authors.forename: Yinping
authors.initials: Y
authors.lastname: Liu
authors.forename: Rachel R
authors.initials: RR
authors.lastname: Caspi
authors.forename: Wai Man
authors.initials: WM
authors.lastname: Wong
authors.forename: Wutian
authors.initials: W
authors.lastname: Wu
authors.forename: Wenwei
authors.initials: W
authors.lastname: Tu
authors.forename: Yu Lung
authors.initials: YL
authors.lastname: Lau
mesh_terms: D019264:Adoptive Transfer; D000595:Amino Acid Sequence; D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D049109:Cell Proliferation / Q000187:drug effects; D003711:Demyelinating Diseases / Q000150:complications / Q000628:therapy; D004681:Encephalomyelitis, Autoimmune, Experimental / Q000150:complications / Q000276:immunology* / Q000628:therapy*; D051858:Forkhead Transcription Factors / Q000378:metabolism; D007074:Immunoglobulin G / Q000627:therapeutic use*; D007371:Interferon-gamma / Q000096:biosynthesis; D020381:Interleukin-17 / Q000096:biosynthesis; D007376:Interleukin-2 / Q000096:biosynthesis / Q000378:metabolism; D053645:Interleukin-2 Receptor alpha Subunit / Q000378:metabolism; D007694:Killer Cells, Natural / Q000187:drug effects / Q000276:immunology* / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D050378:T-Lymphocytes, Regulatory / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D053773:Transforming Growth Factor beta1 / Q000494:pharmacology
chemical_list: D051858:Forkhead Transcription Factors; C498833:Foxp3 protein, mouse; D007074:Immunoglobulin G; D020381:Interleukin-17; D007376:Interleukin-2; D053645:Interleukin-2 Receptor alpha Subunit; D053773:Transforming Growth Factor beta1; D007371:Interferon-gamma