title: Antigen transfer from exosomes to dendritic cells as an explanation for the immune enhancement seen by IgE immune complexes.
abstract: IgE antigen complexes induce increased specific T cell proliferation and increased specific IgG production. Immediately after immunization, CD23(+) B cells capture IgE antigen complexes, transport them to the spleen where, via unknown mechanisms, dendritic cells capture the antigen and present it to T cells. CD23, the low affinity IgE receptor, binds IgE antigen complexes and internalizes them. In this study, we show that these complexes are processed onto B-cell derived exosomes (bexosomes) in a CD23 dependent manner. The bexosomes carry CD23, IgE and MHC II and stimulate antigen specific T-cell proliferation in vitro. When IgE antigen complex stimulated bexosomes are incubated with dendritic cells, dendritic cells induce specific T-cell proliferation in vivo, similar to IgE antigen complexes. This suggests that bexosomes can provide the essential transfer mechanism for IgE antigen complexes from B cells to dendritic cells.
authors.affiliation: Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, Virginia, United States of America.
authors.forename: Rebecca K
authors.initials: RK
authors.lastname: Martin
authors.affiliation: Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, Virginia, United States of America.
authors.forename: Keith B
authors.initials: KB
authors.lastname: Brooks
authors.affiliation: Department of Medical Biochemistry and Microbiology, Biomedical Center, Uppsala University, Uppsala, Sweden.
authors.forename: Frida
authors.initials: F
authors.lastname: Henningsson
authors.affiliation: Department of Medical Biochemistry and Microbiology, Biomedical Center, Uppsala University, Uppsala, Sweden.
authors.forename: Birgitta
authors.initials: B
authors.lastname: Heyman
authors.affiliation: Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, Virginia, United States of America.
authors.forename: Daniel H
authors.initials: DH
authors.lastname: Conrad
mesh_terms: D000818:Animals; D017951:Antigen Presentation / Q000502:physiology*; D000936:Antigen-Antibody Complex / Q000235:genetics / Q000276:immunology*; D001402:B-Lymphocytes / Q000166:cytology / Q000276:immunology; D001693:Biological Transport, Active / Q000235:genetics / Q000276:immunology; D003713:Dendritic Cells / Q000166:cytology / Q000276:immunology*; D055354:Exosomes / Q000235:genetics / Q000276:immunology*; D000949:Histocompatibility Antigens Class II / Q000235:genetics / Q000276:immunology; D007073:Immunoglobulin E / Q000235:genetics / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D018345:Mice, Knockout; D017455:Receptors, IgE / Q000235:genetics / Q000276:immunology; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology
chemical_list: D000936:Antigen-Antibody Complex; D000949:Histocompatibility Antigens Class II; D017455:Receptors, IgE; D007073:Immunoglobulin E