title: CD4(+) T cells from lupus-prone mice are hyperresponsive to T cell receptor engagement with low and high affinity peptide antigens: a model to explain spontaneous T cell activation in lupus.
abstract: Polyclonal CD4(+) T cell activation is characteristic of spontaneous lupus. As a potential explanation for this phenotype, we hypothesized that T cells from lupus-prone mice are intrinsically hyperresponsive to stimulation with antigen, particularly to those peptide ligands having a low affinity for the T cell receptor (TCR). To test this hypothesis, we backcrossed the alpha and beta chain genes of the AND TCR specific for amino acids 88-104 of pigeon cytochrome C (PCC) to the Fas-intact MRL/Mp(+)(Fas-lpr) and to the H-2(k)-matched control backgrounds B10.BR and CBA/CaJ (MRL.AND, B10.AND, and CBA.AND, respectively), and assessed naive CD4(+) TCR transgenic T cell activation in vitro after its encounter with cognate antigen and lower affinity altered peptide ligands (APLs). MRL.AND T cells, compared with control B10.AND and CBA.AND cells, proliferated more when stimulated with agonist antigen. More strikingly, MRL.AND T cells proliferated significantly more and produced more interleukin 2 when stimulated with the APLs of PCC 88-104, having lower affinity for the transgenic TCR. These results imply that one of the forces driving polyclonal activation of alpha/beta T cells in lupus is an intrinsically heightened response to peptide antigen, particularly those with low affinity for the TCR, independent of the nature of the antigen-presenting cell and degree of costimulation.
authors.affiliation: Section of Rheumatology, Department of Medicine, and the Section of Immunobiology, Yale University School of Medicine, New Haven, Connecticut 06520, USA.
authors.forename: G S
authors.initials: GS
authors.lastname: Vratsanos
authors.forename: S
authors.initials: S
authors.lastname: Jung
authors.forename: Y M
authors.initials: YM
authors.lastname: Park
authors.forename: J
authors.initials: J
authors.lastname: Craft
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D002455:Cell Division; D003574:Cytochrome c Group / Q000276:immunology; D008177:Lupus Vulgaris / Q000276:immunology*; D008213:Lymphocyte Activation / Q000276:immunology*; D051379:Mice; D008822:Mice, Transgenic; D018448:Models, Immunological; D008969:Molecular Sequence Data; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000276:immunology*
chemical_list: D003574:Cytochrome c Group; D016693:Receptors, Antigen, T-Cell, alpha-beta