title: Cutting Edge: Marginal Zone Macrophages Regulate Antigen Transport by B Cells to the Follicle in the Spleen via CD21.
abstract: Marginal zone macrophages (MZM) are strategically located in the spleen, lining the marginal sinus where they sense inflammation and capture Ag from the circulation. One of the receptors expressed by MZM is scavenger receptor macrophage receptor with collagenous structure (MARCO), which has affinity for modified self-antigens. In this article, we show that engagement of MARCO on murine macrophages induces extracellular ATP and loss of CD21 and CD62L on marginal zone B cells. Engagement of MARCO also leads to reduction of Ag transport by marginal zone B cells and affects the subsequent immune response. This study highlights a novel function for MZM in regulating Ag transport and activation, and we suggest that MARCO-dependent ATP release regulates this through shedding of CD21 and CD62L. Because systemic lupus erythematosus patients were shown to acquire autoantibodies against MARCO, this highlights a mechanism that could affect a patient's ability to combat infections.
authors.affiliation: Department of Microbiology, Tumor, and Cell Biology, Karolinska Institutet Solna Campus, Karolinska Institutet, SE-171 77 Stockholm, Sweden; Program in Cellular and Molecular Medicine, Children's Hospital, Harvard Medical School, Boston, MA 02115;
authors.forename: Kajsa E
authors.identifier: 0000-0001-5992-0029
authors.initials: KE
authors.lastname: Prokopec
authors.affiliation: Department of Microbiology, Tumor, and Cell Biology, Karolinska Institutet Solna Campus, Karolinska Institutet, SE-171 77 Stockholm, Sweden;
authors.forename: Anna-Maria
authors.identifier: 0000-0002-5346-8737
authors.initials: AM
authors.lastname: Georgoudaki
authors.affiliation: Department of Microbiology, Tumor, and Cell Biology, Karolinska Institutet Solna Campus, Karolinska Institutet, SE-171 77 Stockholm, Sweden;
authors.forename: Silke
authors.identifier: 0000-0002-7051-0933
authors.initials: S
authors.lastname: Sohn
authors.affiliation: Rheumatology Unit, Department of Medicine, Karolinska Institutet Solna Campus, Karolinska Institutet, and Karolinska University Hospital, SE-171 76 Stockholm, Sweden; and.
authors.forename: Fredrik
authors.identifier: 0000-0001-9633-677X
authors.initials: F
authors.lastname: Wermeling
authors.affiliation: Department of Clinical Neuroscience, Karolinska Institutet, SE-171 76 Stockholm, Sweden.
authors.forename: Hans
authors.identifier: 0000-0003-4882-7624
authors.initials: H
authors.lastname: Grönlund
authors.affiliation: Department of Microbiology, Tumor, and Cell Biology, Karolinska Institutet Solna Campus, Karolinska Institutet, SE-171 77 Stockholm, Sweden;
authors.forename: Emma
authors.initials: E
authors.lastname: Lindh
authors.affiliation: Program in Cellular and Molecular Medicine, Children's Hospital, Harvard Medical School, Boston, MA 02115;
authors.forename: Michael C
authors.initials: MC
authors.lastname: Carroll
authors.affiliation: Department of Microbiology, Tumor, and Cell Biology, Karolinska Institutet Solna Campus, Karolinska Institutet, SE-171 77 Stockholm, Sweden; mikael.karlsson@ki.se.
authors.forename: Mikael C I
authors.initials: MC
authors.lastname: Karlsson
mesh_terms: D056704:Adaptive Immunity; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D000941:Antigens / Q000378:metabolism*; D001402:B-Lymphocytes / Q000276:immunology*; D019041:L-Selectin / Q000502:physiology; D008264:Macrophages / Q000502:physiology*; D051379:Mice; D017464:Receptors, Complement 3d / Q000502:physiology*; D011971:Receptors, Immunologic / Q000502:physiology; D013154:Spleen / Q000276:immunology*
chemical_list: D000941:Antigens; C092228:Marco protein, mouse; D017464:Receptors, Complement 3d; D011971:Receptors, Immunologic; D019041:L-Selectin; D000255:Adenosine Triphosphate