Analysis of IgM and IgG Autoatibodies NOD.B10Sn-H2b/J female mice and age and gender-matched C57BL/10 controls
Ontology highlight
ABSTRACT: NOD.B10Sn-H2b/J mice are a mouse model of primary Sjogren's syndrome. We compared IgM and IgG autoantibody levels from NOD.B10Sn-H2b/J females with clinical disease to those of healthy controls.
ORGANISM(S): Mus musculus Rattus norvegicus Homo sapiens
Project description:The aim of the study was to determine B6 and BXD2 mouse sera IgG and IgM reactivity to linear peptide epitopes at different ages. Serum from B6 or BXD2 mice was diluted at 1:200 for IgG-specific analysis or 1:1000 for IgM specific analysis and incubated on a PEPperPRINT peptide microarray platform printed with peptide autoantigens. 80 pre-selected peptides based on a previous screen of pooled mouse serum BXD2 against the PEPperCHIP® Autoimmunity Microarray with 2,733 linear B-cell epitopes were printed in duplicate in 16 copies on a custom PEPperCHIP® Peptide Microarray. Flag (DYKDDDDKGG) and HA (YPYDVPDYAG) control peptides (10 spots each control) were randomly distributed in each array copy as controls. Sera from 2, 5, or 9 month old B6 or BXD2 mice was profiled for anti-mouse IgG or IgM-specific analysis of autoantibody reactivity to the peptide auto-epitopes.
Project description:The aim of the study was to determine B6 and BXD2 mouse sera IgG and IgM reactivity to linear peptide epitopes at different ages. Serum from B6 or BXD2 mice was diluted at 1:200 for IgG-specific analysis or 1:1000 for IgM specific analysis and incubated on a PEPperPRINT peptide microarray platform printed with peptide autoantigens.
Project description:The goal of this study was to determine whether male and female mice with primary Sjogren's disease (pSD) displayed differences in autoreactive IgM and IgG in sera. We also sought to determine whether this reactivity was dependent on the expression of Tlr7.
Project description:Systemic lupus erythematosus is a chronic autoimmune disease with multifactorial ethiopathogenesis. The complement system is involved in both the early and late stages of disease development and organ damage. To better understand autoantibody mediated complement consumption the GAPAID consortium examined ex vivo immune complex formation on autoantigen arrays. We recruited patients with SLE (n=211), with other systemic autoimmune diseases (n=65) and non-autoimmune control subjects (n=149) in two rheumatology tertiary care centers. Standard clinical and laboratory data were collected from all subjects and serum complement levels were determined in SLE patients. The genotype of SNP rs1143679 in the ITGAM gene was also determined. On-chip formation of immune complexes was examined using a functional immunoassay on autoantigen microarray. The amount of antigen-bound IgM, IgG and complement C4 and C3 was quantified on autoantigens comprising nucleic acids, proteins and lipids. Our results show that the relatively high complement consumption of nucleic acids is further increased upon binding of IgM and IgG. This is true even when serum complement levels are decreased due to complement consumption in SLE patients. A negative correlation between serum complement levels and ex vivo complement deposition on nucleic acid autoantigens is demonstrated. On the contrary, most protein and lipid autoantigens show positive correlation with C4 and C3 levels. Genetic analysis reveals that the non-synonymous variant rs1143679 in complement receptor type 3 is associated with an increased production of anti-dsDNA IgG antibodies. Notwithstanding, homozygous carriers of the previously reported susceptible allele (AA) have lower levels of dsDNA specific IgM among SLE patients. Regarding organ involvement we find that besides anti-C1q IgG, low levels of dsDNA specific IgM and low complement C4 binding to C1q are also associated with renal injury. In summary, nucleic acids maintain a skewed complement deposition balance when bound by IgG and IgM, depleting the early classical complement pathway from other physiological processes. Dysfunction of the receptor responsible for complement-mediated apoptotic debris removal promotes the development of autoantibodies targeting nucleic acids. These observations provide serological and genetic evidence for complement-mediated clearance deficiency of apoptotic debris in lupus.
Project description:Immunoglobulin mu (IgM) is a class of mammalian antibodies that are critical for the early stages of adaptive immunity and are the most potent activators of the classical complement cascade. While the relationship between IgM and complement has been appreciated for decades, the structural transitions within IgM upon antigen binding that lead to the activation of the C1 complex remain unresolved. Here we examine the complement activation profiles, binding kinetics, and conformational changes in IgM in different antigen-bound states. Only in the complex with a surface-displayed antigen with multiple Fab arms engaged was the IgM fully capable of driving complement activation. The structural changes within IgM upon antigen binding were monitored by Hydrogen/Deuterium Exchange reveal the predominant structural changes within the Fc core domains upon activation. Collectively, this work establishes key structural and functional qualities that define the complement-active form of IgM.
Project description:Systemic lupus erythematosus is a chronic autoimmune disease with multifactorial ethiopathogenesis. The complement system is involved in both the early and late stages of disease development and organ damage. To better understand autoantibody mediated complement consumption the GAPAID consortium examined ex vivo immune complex formation on autoantigen arrays. We recruited patients with SLE (n=211), with other systemic autoimmune diseases (n=65) and non-autoimmune control subjects (n=149) in two rheumatology tertiary care centers. Standard clinical and laboratory data were collected from all subjects and serum complement levels were determined in SLE patients. The genotype of SNP rs1143679 in the ITGAM gene was also determined. On-chip formation of immune complexes was examined using a functional immunoassay on autoantigen microarray. The amount of antigen-bound IgM, IgG and complement C4 and C3 was quantified on autoantigens comprising nucleic acids, proteins and lipids. Our results show that the relatively high complement consumption of nucleic acids is further increased upon binding of IgM and IgG. This is true even when serum complement levels are decreased due to complement consumption in SLE patients. A negative correlation between serum complement levels and ex vivo complement deposition on nucleic acid autoantigens is demonstrated. On the contrary, most protein and lipid autoantigens show positive correlation with C4 and C3 levels. Genetic analysis reveals that the non-synonymous variant rs1143679 in complement receptor type 3 is associated with an increased production of anti-dsDNA IgG antibodies. Notwithstanding, homozygous carriers of the previously reported susceptible allele (AA) have lower levels of dsDNA specific IgM among SLE patients. Regarding organ involvement we find that besides anti-C1q IgG, low levels of dsDNA specific IgM and low complement C4 binding to C1q are also associated with renal injury. In summary, nucleic acids maintain a skewed complement deposition balance when bound by IgG and IgM, depleting the early classical complement pathway from other physiological processes. Dysfunction of the receptor responsible for complement-mediated apoptotic debris removal promotes the development of autoantibodies targeting nucleic acids. These observations provide serological and genetic evidence for complement-mediated clearance deficiency of apoptotic debris in lupus.
Project description:Sera were acquired from the Sjogren's International Collaborative Clinical Alliance (SICCA) biorepository and were assayed for IgG autoantibodies. The autoantigen array was performed to identify the specific autoantibodies that were enriched in pSS patients.
Project description:The aim of the array was to determine the B6 mouse sera IgG and IgM reactivity profile to linear peptide epitopes. Pooled sera from three 6-9 month old B6 mice was diluted at 1:200 for IgG specific analysis or 1:1000 for IgM specific analysis and incubated on a PEPperPRINT peptide microarray platform printed with peptide autoantigens Pooled sera from three 6-9 month old B6 mice was profiled for IgG or IgM-specific analysis of autoantibody reactivity to peptide auto-epitopes printed in duplicate on a PepperPrint Chip.
Project description:The aim of the array was to determine the BXD2 mouse sera IgG and IgM reactivity profile to linear peptide epitopes. Pooled sera from three 6-9 month old BXD2 mice was diluted at 1:200 for IgG specific analysis or 1:1000 for IgM specific analysis and incubated on a PEPperPRINT peptide microarray platform printed with peptide autoantigens In this study, pooled sera from three 6-9 month old BXD2 mice was profiled for IgG and IgM specific autoantibody reactivity to peptide auto-epitopes printed in duplicate on a PepperPrint Chip.