title: CD64 expression distinguishes monocyte-derived and conventional dendritic cells and reveals their distinct role during intramuscular immunization.
abstract: Although most vaccines are administered i.m., little is known about the dendritic cells (DCs) that are present within skeletal muscles. In this article, we show that expression of CD64, the high-affinity IgG receptor FcγRI, distinguishes conventional DCs from monocyte-derived DCs (Mo-DCs). By using such a discriminatory marker, we defined the distinct DC subsets that reside in skeletal muscles and identified their migratory counterparts in draining lymph nodes (LNs). We further used this capability to analyze the functional specialization that exists among muscle DCs. After i.m. administration of Ag adsorbed to alum, we showed that alum-injected muscles contained large numbers of conventional DCs that belong to the CD8α(+)- and CD11b(+)-type DCs. Both conventional DC types were capable of capturing Ag and of migrating to draining LNs, where they efficiently activated naive T cells. In alum-injected muscles, Mo-DCs were as numerous as conventional DCs, but only a small fraction migrated to draining LNs. Therefore, alum by itself poorly induces Mo-DCs to migrate to draining LNs. We showed that addition of small amounts of LPS to alum enhanced Mo-DC migration. Considering that migratory Mo-DCs had, on a per cell basis, a higher capacity to induce IFN-γ-producing T cells than conventional DCs, the addition of LPS to alum enhanced the overall immunogenicity of Ags presented by muscle-derived DCs. Therefore, a full understanding of the role of adjuvants during i.m. vaccination needs to take into account the heterogeneous migratory and functional behavior of muscle DCs and Mo-DCs revealed in this study.
authors.affiliation: Centre d'Immunologie de Marseille-Luminy, Université de la Méditerranée, Case 906, 13288 Marseille Cedex 9, France.
authors.forename: Christelle
authors.initials: C
authors.lastname: Langlet
authors.forename: Samira
authors.initials: S
authors.lastname: Tamoutounour
authors.forename: Sandrine
authors.initials: S
authors.lastname: Henri
authors.forename: Hervé
authors.initials: H
authors.lastname: Luche
authors.forename: Laurence
authors.initials: L
authors.lastname: Ardouin
authors.forename: Claude
authors.initials: C
authors.lastname: Grégoire
authors.forename: Bernard
authors.initials: B
authors.lastname: Malissen
authors.forename: Martin
authors.initials: M
authors.lastname: Guilliams
mesh_terms: D000276:Adjuvants, Immunologic; D000534:Alum Compounds; D000818:Animals; D002454:Cell Differentiation; D003713:Dendritic Cells / Q000276:immunology*; D007114:Immunization; D007273:Injections, Intramuscular; D007371:Interferon-gamma / Q000096:biosynthesis; D051379:Mice; D009000:Monocytes / Q000276:immunology*; D018482:Muscle, Skeletal / Q000276:immunology*; D017452:Receptors, IgG / Q000096:biosynthesis* / Q000378:metabolism; D013601:T-Lymphocytes / Q000276:immunology; D014612:Vaccines / Q000008:administration & dosage / Q000276:immunology
chemical_list: D000276:Adjuvants, Immunologic; D000534:Alum Compounds; C485701:Fcgr1 protein, mouse; D017452:Receptors, IgG; D014612:Vaccines; C041524:aluminum sulfate; D007371:Interferon-gamma