title: Cutting edge: recombinase-activating gene expression and V(D)J recombination in CD4+CD3low mature T lymphocytes.
abstract: The recombinase-activating genes, RAG-1 and RAG-2, can be expressed by a subset of B cells within germinal centers, where they mediate secondary V(D)J rearrangements. This receptor revision mechanism could serve either receptor diversification or tolerance-induced functions. Alternatively, it might rescue those cells the receptors of which have been damaged by somatic mutation. Less is known about the occurrence of similar mechanisms in T cells. Here we show that mature T cells with defective TCR surface expression can express RAG genes and are capable of initiating secondary V(D)J rearrangements. The possibility that a cell rescue mechanism based on the generation of a novel Ag receptor might be active in peripheral T cells is envisaged.
authors.affiliation: S. Maugeri Foundation, Instituto di Ricovero e Cura a Carottere Scientifico (IRCCS) Pavia, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Lantelme
authors.forename: B
authors.initials: B
authors.lastname: Palermo
authors.forename: L
authors.initials: L
authors.lastname: Granziero
authors.forename: S
authors.initials: S
authors.lastname: Mantovani
authors.forename: R
authors.initials: R
authors.lastname: Campanelli
authors.forename: V
authors.initials: V
authors.lastname: Monafo
authors.forename: A
authors.initials: A
authors.lastname: Lanzavecchia
authors.forename: C
authors.initials: C
authors.lastname: Giachino
mesh_terms: D017252:CD3 Complex / Q000096:biosynthesis*; D015704:CD4 Antigens / Q000096:biosynthesis*; D002454:Cell Differentiation / Q000276:immunology; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000235:genetics*; D004789:Enzyme Activation / Q000235:genetics / Q000276:immunology; D015971:Gene Expression Regulation, Enzymologic / Q000276:immunology; D015329:Gene Rearrangement, T-Lymphocyte; D018398:Homeodomain Proteins / Q000096:biosynthesis / Q000235:genetics*; D006801:Humans; D009687:Nuclear Proteins; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000096:biosynthesis / Q000235:genetics*; D016176:T-Lymphocyte Subsets / Q000166:cytology / Q000201:enzymology* / Q000276:immunology* / Q000378:metabolism; D019895:Transposases / Q000235:genetics / Q000378:metabolism*
chemical_list: D017252:CD3 Complex; D015704:CD4 Antigens; D004268:DNA-Binding Proteins; D018398:Homeodomain Proteins; D009687:Nuclear Proteins; C499311:RAG2 protein, human; D016693:Receptors, Antigen, T-Cell, alpha-beta; C064655:V(D)J recombination activating protein 2; C064658:RAG-1 protein; D019895:Transposases