title: Prevention of T cell activation by interference of internalized intravenous immunoglobulin (IVIg) with MHC II-dependent native antigen presentation.
abstract: Activation of self-reactive CD4(+) T cells plays a central role in the initiation and maintenance of autoimmune diseases. We recently reported that intravenous immunoglobulin (IVIg) inhibits the MHC II-restricted CD4(+) T cell activation induced by the presentation of immune complexes. Because native antigens can also play a role in the induction of several autoimmune diseases, we determined whether IVIg could also affect CD4(+) T cell activation following presentation of native antigens by APCs. Here we report that IVIg significantly reduces the activation of CD4(+) T cells by native ovalbumin. The inhibitory effect is FcγR-independent and occurs following internalization of IVIg inside APCs, where it interferes with the intracellular events leading to MHC II-dependent antigen presentation. The effect of IVIg on native antigen presentation could therefore contribute to dampen the autoimmune reaction by reducing CD4(+) T cell activation and the subsequent inflammatory response induced by these cells.
authors.affiliation: Department of Research and Development, Héma-Québec, Québec, Canada. eric.aubin@hema-quebec.qc.ca
authors.forename: Éric
authors.initials: É
authors.lastname: Aubin
authors.forename: Dominic Paquin
authors.initials: DP
authors.lastname: Proulx
authors.forename: Patrick
authors.initials: P
authors.lastname: Trépanier
authors.forename: Réal
authors.initials: R
authors.lastname: Lemieux
authors.forename: Renée
authors.initials: R
authors.lastname: Bazin
mesh_terms: D000818:Animals; D017951:Antigen Presentation / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D002460:Cell Line; D003713:Dendritic Cells / Q000276:immunology; D005260:Female; D000949:Histocompatibility Antigens Class II / Q000276:immunology*; D016756:Immunoglobulins, Intravenous / Q000276:immunology* / Q000494:pharmacology; D008213:Lymphocyte Activation / Q000187:drug effects / Q000276:immunology*; D008264:Macrophages / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D008808:Mice, Inbred CBA; D010047:Ovalbumin / Q000276:immunology
chemical_list: D000949:Histocompatibility Antigens Class II; D016756:Immunoglobulins, Intravenous; D010047:Ovalbumin