title: Cutting edge: Expression of FcγRIIB tempers memory CD8 T cell function in vivo.
abstract: During reinfection, high-affinity IgG Abs form complexes with both soluble Ag and Ag displayed on the surface of infected cells. These interactions regulate cellular activation of both innate cells and B cells, which express specific combinations of activating FcγRs (FcγRI, FcγRIII, FcγRIV) and/or the inhibitory FcγR (FcγRIIB). Direct proof for functional expression of FcγR by Ag-specific CD8 T cells is lacking. In this article, we show that the majority of memory CD8 T cells generated by bacterial or viral infection express only FcγRIIB, and that FcγRIIB could be detected on previously activated human CD8 T cells. Of note, FcγR stimulation during in vivo Ag challenge not only inhibited the cytotoxicity of memory CD8 T cells against peptide-loaded or virus-infected targets, but FcγRIIB blockade during homologous virus challenge enhanced the secondary CD8 T cell response. Thus, memory CD8 T cells intrinsically express a functional FcγRIIB, permitting Ag-Ab complexes to regulate secondary CD8 T cell responses.
authors.affiliation: Interdisciplinary Graduate Program in Immunology, University of Iowa, Iowa City, IA 52242;
authors.forename: Gabriel R
authors.initials: GR
authors.lastname: Starbeck-Miller
authors.forename: Vladimir P
authors.initials: VP
authors.lastname: Badovinac
authors.forename: Daniel L
authors.initials: DL
authors.lastname: Barber
authors.forename: John T
authors.initials: JT
authors.lastname: Harty
mesh_terms: D000818:Animals; D000941:Antigens / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism*; D002460:Cell Line; D003602:Cytotoxicity, Immunologic; D018984:Epitopes, T-Lymphocyte / Q000276:immunology; D005786:Gene Expression Regulation; D006801:Humans; D007156:Immunologic Memory / Q000235:genetics*; D008216:Lymphocytic Choriomeningitis / Q000276:immunology; D008217:Lymphocytic choriomeningitis virus / Q000276:immunology; D051379:Mice; D018345:Mice, Knockout; D017452:Receptors, IgG / Q000235:genetics* / Q000378:metabolism
chemical_list: D000941:Antigens; D018984:Epitopes, T-Lymphocyte; D017452:Receptors, IgG