Antigenic domains on the U1 small nuclear ribonucleoprotein-associated 70K polypeptide: A comparison of regions selectively recognized by human and mouse autoantibodies and by monoclonal antibodies

Takeda, Yoshihiko; Nyman, Ulf; Winkler, Anne; Wise, Kim S.; Hoch, Sallie O.; Pettersson, Ingvar; Anderson, Sharon K.; Wang, Richard J.; Wang, Grace S.; Sharp, Gordon C.

doi:10.1016/s0090-1229(06)80007-3

Cited by 25 publications

(22 citation statements)

References 35 publications

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“…In some of these studies, peptide forms of 70k extending to residue 195 but not to 205 were used, and 70k epitopes encompassing residues within the 180 -205 region were identified (22)(23)(24)(25). We found that a 1-195 form of 70k was not strongly recognized by our apoptosis-only anti-70k sera, an intermediate result between the strong reactivity with the 1-205 peptide and the often absent reactivity of the 1-180 peptide (data not shown).…”

Section: Figurementioning

confidence: 99%

A Major B Cell Epitope Present on the Apoptotic but Not the Intact Form of the U1-70-kDa Ribonucleoprotein Autoantigen

Greidinger

Foecking

Magee

et al. 2004

The Journal of Immunology

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Apoptotically modified forms of autoantigens have been hypothesized to participate in lupus immunopathogenesis. This study identifies a major B cell epitope present on the apoptotic but not the intact form of the U1-70-kDa ribonucleoprotein lupus autoantigen (70k). Human autoimmune sera with strong recognition of apoptotic 70k and minimal recognition of intact 70k were identified and tested for reactivity to truncated forms of 70k by immunoblot and ELISA. Patient sera that preferentially recognized apoptotic 70k were specific for an epitope dependent on residues 180–205 of the protein. This epitope was also recognized by 19 of 28 (68%) intact anti-70k-positive autoimmune human sera with Abs also recognizing apoptotic but not the intact form 70k, but only 1 of 9 (11%) intact 70k-positive sera without such Abs (Fisher’s exact, p = 0.0055). Immunization of HLA-DR4-transgenic C57BL/6 mice with a peptide containing this epitope induced anti-70k immunity in 13 of 15 mice, including Abs recognizing apoptotic but not intact forms of autoantigens in 12 of 15 mice. Anti-70k responder mice also developed spreading of immunity to epitopes on the endogenous form of 70k, and proliferative lung lesions consistent with those described in patients with anti-70k autoimmunity. Thus, a major epitope in the B cell response to U1-70 kDa localizes to the RNA binding domain of the molecule, overlaps with the most common T cell epitope in the anti-70k response, and is not present on the intact form of the 70k molecule. Immunization of mice against this epitope induces an immune response with features seen in human anti-70k autoimmune disease.

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Section: Figurementioning

confidence: 99%

A Major B Cell Epitope Present on the Apoptotic but Not the Intact Form of the U1-70-kDa Ribonucleoprotein Autoantigen

Greidinger

Foecking

Magee

et al. 2004

The Journal of Immunology

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“…For some experiments, forms of U1-70kDa-MBP were further purified by elution of the relevant band cut from 10% SDS-PAGE preparative gels as previously described (26). Caspase-cleaved U1-70kDa was produced by incubating intact U1-70kDa fusion protein with caspase-3 (R&D Systems, Minneapolis, MN) in buffer containing 10 mM HEPES (pH 7.4), 2 mM EDTA, 5 mM DTT, and 1% Nonidet P-40 as previously described (6).…”

Section: Recombinant Agmentioning

confidence: 99%

T Cell Immunity in Connective Tissue Disease Patients Targets the RNA Binding Domain of the U1-70kDa Small Nuclear Ribonucleoprotein

Greidinger

Foecking

Schäfermeyer

et al. 2002

The Journal of Immunology

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Although the T cell dependence of autoimmune responses in connective tissue diseases has been well established, limited information exists regarding the T cell targeting of self Ags in humans. To characterize the T cell response to a connective tissue disease-associated autoantigen, this study generated T cell clones from patients using a set of peptides encompassing the entire linear sequence of the 70-kDa subunit of U1 snRNP (U1-70kDa) small nuclear ribonucleoprotein. Despite the ability of U1-70kDa to undergo multiple forms of Ag modification that have been correlated with distinct clinical disease phenotypes, a remarkably limited and consistent pattern of T cell targeting of U1-70kDa was observed. All tested T cell clones generated against U1-70kDa were specific for epitopes within the RNA binding domain (RBD) of the protein. High avidity binding of the RBD with U1-RNA was preserved with the disease-associated modified forms of U1-70kDa tested. The high avidity interaction between the U1-RBD on the polypeptide and U1-RNA may be critical in immune targeting of this region in autoimmunity. The T cell autoimmune response to U1-70kDa appears to have less diversity than is seen in the humoral response; and therefore, may be a favorable target for therapeutic intervention.

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“…2A). Nyman et al [36] characterized a major epitope between residues 135±194, and Takeda et al [37] demonstrated that the sequence 94±194 contained immunodominant epitope(s) recognized by both IgG and IgM-class antibodies. Welin Henrinksson et al [38] studied the antigenicity of chimeric proteins assembled from the highly conserved Drosophila Melanogaster 70K protein grafted with human 70K fragments, and showed that residues 99±128 of the human protein are essential for recognition by both human and canine anti-RNP autoantibodies.…”

Section: K Epitopesmentioning

confidence: 99%

“…Using recombinant fusion proteins, Takeda et al [37] found that seven out of eight MRL/lpr mice, developed exclusively autoantibodies reacting with domain 94± 194 (the remaining one produced antibodies against fragment 195±259). We have recently identified several epitopes in the mouse U1±70K protein using 20 16-to 25-mer overlapping peptides [42].…”

Section: K Epitopesmentioning

confidence: 99%

Key Sequences Involved in the Spreading of the Systemic Autoimmune Response to Spliceosomal Proteins

Monneaux

Muller

2001

Scand J Immunol

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Immune spreading to multiple intracellular antigens is likely to be of primary importance in organ-specific and systemic autoimmune diseases. A number of mechanisms by which immune spreading may occur from only a single autoreactive epitope have been proposed. Search for an initiator or early epitope thus represents an important area of investigation. For example, many studies have focused on the identification of epitopes recognized by the antibodies from both patients with systemic lupus erythematosus (SLE) and lupus-prone mice. Recently, an autoepitope present in the 70K U1 ribonucleo protein (RNP) and recognized by CD4 1 T cells from lupus mice has also been identified. Here, we analyze the results of B-and T-cell-epitope mapping studies of several RNPs present in the spliceosome and propose a model of epitope spreading. In this model, a consensus sequence (the RNP motif) conserved in many nuclear, nucleolar and cytoplasmic antigens, might play a role as`driver' epitope. This hypothesis is based on the observation that this sequence is recognized by CD4 1 T cells from lupus mice and is often targeted by autoantibodies, very early during the course of the disease. Targeting this region that is repeated in different self-antigens, might represent an interesting strategy to interfere with the continuous T-cell stimulation and exposure to specific antigens.

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Antigenic domains on the U1 small nuclear ribonucleoprotein-associated 70K polypeptide: A comparison of regions selectively recognized by human and mouse autoantibodies and by monoclonal antibodies

Cited by 25 publications

References 35 publications

A Major B Cell Epitope Present on the Apoptotic but Not the Intact Form of the U1-70-kDa Ribonucleoprotein Autoantigen

A Major B Cell Epitope Present on the Apoptotic but Not the Intact Form of the U1-70-kDa Ribonucleoprotein Autoantigen

T Cell Immunity in Connective Tissue Disease Patients Targets the RNA Binding Domain of the U1-70kDa Small Nuclear Ribonucleoprotein

Key Sequences Involved in the Spreading of the Systemic Autoimmune Response to Spliceosomal Proteins

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