Herpes viruses in multicase families with rheumatoid arthritis and systemic lupus erythematosus.
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Arthritis, Rheumatoid↗
Biomedical subjects
M M Newkirk
Publications and source records attributed to M M Newkirk.
Differential clearance of glycoforms of IgG in normal and autoimmune-prone mice.
In order to understand better the origins of the elevated levels of the glycoform of IgG that lacks galactose on both arms of the oligosaccharide chain (G0%) located in the Fc, which occurs in man and mouse with age, and in particular in autoimmune disease, we investigated the clearance of two glycosylated forms of IgG2a and IgG1 in normal (BALB/c) and autoimmune-prone (MRL/1pr, MRL/+, and non-obese diabetic (NOD)) mice. To investigate the possibility of different rates of catabolism, enzymatically generated glycoforms of monomeric IgG1 and IgG2a (fully glycosylated or G0%), were iodinated and injected into the tail vein of the mice. We found that the G0% IgG2a remained in circulation significantly longer than the fully glycosylated variants, in all of the mouse strains tested. In contrast, the two forms of IgG1 had similar kinetics in all the autoimmune-prone mice, whereas in BALB/c, there was a longer half-life (t1/2) for G0% IgG1. These data suggest that there may be differences in the ability of the IgG glycoforms to bind to the Fc gamma receptors, in particular Fc gamma RI. The clearance rates were found to vary among the strains studied, with MRL/1pr having the fastest catabolic rates for all glycoforms and IgG subclasses tested. This appeared to be due to the presence of circulating IgG and IgM rheumatoid factors (RF). There were significantly increased frequencies and titres for both IgM and IgG RF in MRL/1pr mice compared with the other strains. In contrast, interferon-gamma, known to induce the Fc gamma RI, was found to be similar in the sera, in all of the strains of mice examined. These results suggest that RF probably play an important biological function in the MRL/1pr mice and aid in the clearance of circulating IgG. Our study shows that the state of glycosylation of IgG affects the t1/2 in vivo, and that by removing the terminal sugars (sialic acid and galactose), the antibody (IgG2a) will remain in circulation significantly longer. These observations may thus provide a partial explanation for the increase in relative percentage of this glycoform that occurs with age.
Animals↗
Rheumatic disease patients, prone to Sjögren's syndrome and/or lymphoma, mount an antibody response to BHRF1, the Epstein-Barr viral homologue of BCL-2.
The IgG response to Epstein-Barr virus (EBV) early antigens [BHRF1 (p 17.1), the viral homologue of bcl-2, and BMRF1 (p50.10), a DNA binding protein] was measured in patients with rheumatic disease to see whether there was any association with lymphoma. Patients with rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), Sjögren's syndrome (SS), rheumatic disease patients with lymphoma, patients with lymphoma who did not have a rheumatic disease and normal individuals were tested for the presence of anti-EA peptide antibodies by ELISA. Whereas antibodies to early EBV peptides were detected only in one normal individual, patients with rheumatic diseases, especially those with either SS and/or lymphoma, had a much higher frequency of antibody detection. Antibodies to BMRF1 p50.10 were found in 7-50% of patients, and to BHRF1 p17.1 in 4-27%, depending on the group studied. Patients with lymphoma lacking a rheumatic disease had a 2-fold lower frequency of anti-BHRF1 antibodies, compared to the lymphoma plus rheumatic disease group. The increased immune response to the EBV EA proteins in the rheumatic diseases probably reflects the presence of reactivated virus, and the BHRF1 protein (the viral homologue to bcl-2) could, via inhibiting apoptosis, contribute to the lymphoproliferative nature of these diseases.
Adult↗
Generation of diversity in a human anti-viral response.
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Antibodies, Monoclonal↗
Rheumatoid factor avidity in patients with rheumatoid arthritis: identification of pathogenic RFs which correlate with disease parameters and with the gal(0) glycoform of IgG.
The standard ELISA for measuring rheumatoid factor (RF) binding was modified by treatment after the RF-Fc interaction with 2 M guanidine, which allowed a measurement of the avidity of the interaction. Incubation with 4 M guanidine eliminated RF binding. There was a direct correlation (r = 0.99) between the avidity as measured by the modified guanidine ELISA, and the dissociation constant for monoclonal RFs, as measured by competitive ELISA. Of the seropositive rheumatoid arthritis (RA) patients tested, 47% had high-avidity RFs (> or = 8% RF binding remaining after guanidine treatment). Tender joint count scores were significantly higher in the high avidity group (p = 0.05), whereas there was no significant difference in the ages, disease duration, sedimentation rate, RF titer or serum Ig levels compared to those with low-avidity RFs. Additionally 58% of those with high-avidity RFs had subcutaneous nodules, compared to 40% of the low-avidity group. A significantly higher number of nodules was present in the high-avidity RF group compared to those with low-avidity RFs (p = 0.03). Interestingly, the RF avidity was significantly higher in isolated immune complexes (IC), compared to that in circulating IgM RFs (p = 0.01). The RF avidity correlated with the presence of the glycoform of IgG lacking galactose in both circulating and IC-derived IgG (p = 0.003 and 0.009 respectively). Information about the strength of binding to Fc identifies a subgroup of IgM RFs that are likely pathological in patients with RA, as well as a specific glycoform of the target antigen.
Antibodies↗
Anti-DNA and anti-platelet specificities of SLE-derived autoantibodies: evidence for CDR2H mutations and CDR3H motifs.
Although polyreactivity appears to be a characteristic feature of natural autoantibodies, polyreactive anti-DNA autoantibodies can be derived both from patients with autoimmune disease and from normal individuals. It is unclear whether these autoantibodies differ depending on their origin, but previous studies from our laboratory have suggested that polyreactive systemic lupus erythematosus (SLE)-derived platelet-binding anti-DNA autoantibodies have more restricted antigen reactivity and greater functional activity than normal-derived polyreactive autoantibodies. The objective of the present study was to characterize the VH and VL region sequences of 10 human hybridoma anti-DNA autoantibodies derived from peripheral blood lymphocytes of different origins [SLE, rheumatoid arthritis (RA), or normal] to determine whether there are structural differences between these autoantibodies. We show that although some unmutated germline structures (VH and VL) are represented, these are not restricted to anti-DNA autoantibodies from normal individuals and that two normal-derived anti-DNA antibodies showed quite extensively mutated VH genes. However, these mutations, unlike those found in the CDR2H of several of the SLE-derived antibodies, did not appear to be antigen-selected. Three different amino acid motifs, putatively involved in antigen binding specificity, were observed in the CDR3H segments of some of the autoantibodies. One was the previously described YYGSG motif, which was found in a normal-derived anti-DNA autoantibody, while two new potential motifs were observed only in SLE-derived platelet-binding anti-DNA autoantibodies. These data suggest that antigenic and functional differences between SLE-derived and normal-derived platelet-binding anti-DNA autoantibodies may be due to antigen-selected mutations in the CDR2H and specific amino acid motifs in the CDR3H.
Amino Acid Sequence↗
Immunoglobulin gene usage in the human anti-pathogen response.
The human antibody response to foreign pathogens is generated to a relatively small number of target surface proteins and carbohydrates that nonetheless have an extensive array of epitopes. The study of human monoclonal antibodies to different pathogens shows that there are a diversity of mechanisms used to generate a sufficient repertoire of antibodies to combat the invading pathogens. Although many different immunoglobulin gene elements are used to construct the anti-pathogen response, some elements are used more often than would be expected if all elements were used randomly. For example, the immune response to Haemophilus influenzae polysaccharide appears to be quite narrow, being restricted primarily to a specific heavy-chain gene, 3-15, and a lambda light-chain family II member, 4A. In contrast, for the immune response to cytomegalovirus proteins, a wider group of gene elements is needed. It is also surprising that despite an investigator bias for IgG- rather than IgM-secreting immortal B cells (because of their high affinity and neutralizing abilities), 26% of light chains and 13% of heavy chains showed a very low level of somatic mutation, equivalent to an IgM molecule that has not undergone affinity maturation. Although some highly mutated IgG molecules are present in the anti-pathogen response, most of the monoclonal antibodies specific for viruses or bacteria have a level of somatic hypermutation similar to that of the adult IgM repertoire. A number of studies have shown that there are similarities in the antibody responses to pathogens and to self (autoantibodies).(ABSTRACT TRUNCATED AT 250 WORDS)
Antibody Formation↗
Herpes viruses in multicase families with rheumatoid arthritis.
OBJECTIVE: To investigate the rate and extent of infection by Epstein-Barr virus (EBV), cytomegalovirus, and herpesvirus 6 in families (affected and nonaffected members) with multiple cases of rheumatoid arthritis (RA). METHODS: Viral DNA was detected by polymerase chain amplification in cells from saliva and peripheral blood. Human leukocyte antigen pedigrees were characterized. RESULTS: Viral DNA, particularly EBV, was detected in increased frequency (p = 0.029) in the patients with RA compare to their nonaffected relatives. CONCLUSION: We suggest that in RA multicase families, increased frequency of viral infection is likely a consequence of the disease state and/or due to gene(s) as yet unidentified.
Aged↗
Impaired release of sCD23 by activated B-cells from RA patients.
To determine the basis of a differential response among B-cells derived from rheumatoid arthritis (RA) patients and their normal counterpart to anti-CD3-activated T-cells (HUT-78 CD4+), B-cell responsiveness was measured in vitro with a focus on IgG and IgM secretion, the ability to differentiate into plasma cells, and the release of soluble CD23 (sCD23) into the culture media. In the patients with RA, plasma sCD23 levels were measured and studied to see if it related to the rheumatoid factor (RF) titer, age, sera immunoglobulin, therapy, and disease activity. Patients with RA were found to have a significantly increased level of sCD23 in the plasma when compared to control individuals, yet their peripheral blood B-cells were unable to secrete normal levels of sCD23 following in vitro stimulation by T-cells. The plasma level of sCD23 found in the RA patients correlated (P < 0.0001) with the RF titer. B-cells from the RA patients secreted significantly increased amounts of IgG and IgM after in vitro stimulation by T-cells. It appears that peripheral blood B-cells of RA patients are more activated initially and it is likely that at the time of coculture with T-cells they had already passed through the narrow window in cell maturation when sCD23 is released.
Adult↗
Monospecific but not polyreactive human hybridoma rheumatoid factors exhibit preferential binding specificities for IgG3 and IgG4.
Among 38 human hybridoma-derived monoclonal rheumatoid factors (RFs) generated from patients with either rheumatoid arthritis (RA) or systemic lupus erythematosus (SLE), two groups of RFs can be identified. Monospecific RFs were derived primarily from patients with RA and are characterized by a binding specificity for IgG3 and/or IgG4. Polyreactive RFs were derived largely from patients with SLE and show a broader pattern of reactivity to all four isotypes of IgG. Neither population of RFs was exclusive to either disease. The binding specificities identified appear to be different from the RFs isolated from patients with mixed cryoglobulinemia and may reflect a different antigen selection mechanism.
Adult↗
Restricted variable region gene usage and possible rheumatoid factor relationship among human monoclonal antibodies specific for the AD-1 epitope on cytomegalovirus glycoprotein B.
The nucleotide sequences of the variable region genes encoding five different human, high affinity antibodies, specific for the major neutralization determinant (AD-1) expressed by human cytomegalovirus glycoprotein B (gp58/116), have been determined. Three of the five heavy chain variable regions belonged to the small VHV-family, although they combined with a diverse set of light chains (V kappa IIIb, V lambda II and V lambda III). The other two antibodies belonged to VH-families III and IV. One of the VHV-family genes most likely originated from a previously unreported germline gene or allele, since it carries a nine nucleotide insert in framework 1. In addition, V lambda-genes showed variable homology (77-95%) to known germline sequences, while V kappa-genes showed high homology (approximately 98%) with their proposed germline origin. Despite the close homology of the V kappa IIIb-gene used to express one of the antibodies with its corresponding germline gene, the protein did not strongly express some idiotypes associated with this light chain family. There is, thus, no direct relation between the expression of these crossreactive idiotypes and the use of even modestly mutated light chains belonging to this V kappa-family, which has been implicated in the development of anti-idiotypic networks possibly inducing autoantibodies, such as rheumatoid factors.
Amino Acid Sequence↗
Structural characteristics of four human hybridoma antibodies specific for the pp65 protein of the human cytomegalovirus and their relationship to human rheumatoid factors.
Four human hybridoma antibodies directed against the human cytomegalovirus (CMV) were characterized with respect to their immunoglobulin gene usage and expression of rheumatoid factor (RF) associated idiotypes and variable region epitopes. The aims of these experiments were: (1) to characterize the immunoglobulin gene usage of four antibodies directed against a single protein of a human pathogen; and (2) to examine how this humoral response may be linked to the production of RFs, autoantibodies found in the majority of patients with rheumatoid arthritis (RA). All four anti-CMV antibodies were of the gamma heavy chain isotype and were specific for the immunodominant 65 kDa viral matrix phosphoprotein (pp65). The four anti-pp65 antibodies expressed different light (L) and heavy (H) chain variable region gene combinations. These were: VkIII/VH3, V lambda 1/VH3, V lambda 1/VH4 and V lambda 3/VH3, respectively for the HCV-2, HCV-3, HCV-63 and HCV-65 hybridoma cell lines. Although none had RF activity, each of these antibodies expressed a unique set of RF-associated determinants, implying different three-dimensional configurations of the variable regions of these antibodies. The HCV-2 antibody, however, had the most extensive similarities to human RFs since it not only expressed the greatest number of RF-associated determinants but also had a protein sequence that was very homologous to RFs of the "Po" idiotypic family. Furthermore, predicted germline gene usage by anti-CMV antibodies and RFs suggest that some are encoded by identical or similar genes and that the different specificities are achieved by somatic mutations in the L and H chain complementarity determining regions (CDRs) and genetic diversity in the H chain CDR3.
Amino Acid Sequence↗
Detection of cytomegalovirus, Epstein-Barr virus and herpes virus-6 in patients with rheumatoid arthritis with or without Sjögren's syndrome.
The frequency of latent viral infection by cytomegalovirus (CMV), Epstein-Barr virus (EBV) and herpes virus-6 (HHV-6) was investigated in patients with RA with or without Sjögren's syndrome (SS) and in normal controls. Virus presence was determined by polymerase chain amplification of DNA isolated from peripheral blood mononuclear or polymorphonuclear cells and/or saliva-derived mononuclear/epithelial cells. Anti-viral antibodies and autoantibodies were also assayed. Patients with RA both with and without SS were found to have a significantly increased frequency of latent viral infection (two-fold higher, P = 0.035 for EBV and seven-fold higher, P = 0.018 for HHV-6) compared to normal controls but only in cells isolated from saliva. The increased frequency of virally infected cells from the saliva of patients with RA, regardless of the SS status, when compared to normal controls may reflect the ongoing inflammatory process, the impact of therapy and/or a less effective local immune responsiveness.
Aged↗
A human rheumatoid factor C304 shares VH and VL gene usage with antibodies specific for ubiquitous human viral pathogens.
Analysis of the variable region gene sequences of a human hybridoma rheumatoid factor (RF), derived from a patient with rheumatoid arthritis (RA), revealed the expression of genes from the V lambda I and VH3 families. Specifically, the C304 RF had rearranged the DPL8/Humlv1042 and VH26 germline VL and VH genes, respectively. This gene usage has been observed in the rearrangement of human anti-viral antibodies specific for the herpes group of viruses. This overlap between the autoimmune and anti-viral antibody gene repertoires suggests a possible structural relationship between the immune response directed against ubiquitous pathogens and the induction of RF production.
Amino Acid Sequence↗
Viral induction of the human autoantigen calreticulin.
Specific but ubiquitous cytoplasmic proteins are the targets of autoantibodies such as anti-Ro/SS-A, anti-La/SS-B, and anti-calreticulin. These antibodies may be pathogenic in systemic lupus erythematosus (SLE) and Sjogren's syndrome (SS). Tissue localization of the pathogenic process could be best explained by an abnormal expression of these cytoplasmic proteins. Several factors could likely displace the host proteins to the cell surface. This study was designed to use cytomegalovirus (CMV) infected human fibroblasts (MRC-5) as a model, to test whether a viral infection would induce the expression of the human autoantigen(s). Expression of Ro/SS-A, calreticulin, and MHC class I antigens, both in the cytoplasm and on the cell surface, was examined by a fixed cell ELISA, immunofluorescence, and immunoblotting. Infection of fibroblasts with CMV was found to increase the cell surface expression of calreticulin (p = 0.0314), but not the 60KD Ro/SS-A. Cytoplasmic expression of both the autoantigens tested increased following CMV infection. Enhanced expression of class I MHC was detected on the cell surface in response to the virus infection. The expression of the autoantigens and MHC class I polypeptides, as well as the virally induced elevated mitotic rate, diminished after 24 h of infection. Viral infection was found to alter the distribution of host cell proteins, including autoantigens. Cell surface expression of calreticulin could provide a target for circulating autoantibody and contribute to the autoimmune process.
Amino Acid Sequence↗
Reversible lymphomas.
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Arthritis, Rheumatoid↗
Restricted immunoglobulin variable region gene usage by hybridoma rheumatoid factors from patients with systemic lupus erythematosus and rheumatoid arthritis.
Rheumatoid factors (RFs) are autoantibodies that are produced by approximately 75% of patients with rheumatoid arthritis (RA). Their role in pathogenesis is not well understood. In this study of 81 human hybridoma IgM antibodies derived from unstimulated peripheral blood B-cells of patients with RA and systemic lupus erythematosus (SLE), we have demonstrated that idiotypes associated with RFs derived from patients with mixed cryoglobulinemia were expressed by approximately 60% of RFs and 6% of IgM antibodies lacking RF activity. The specificity of the RFs for the Fc portion of IgG only (monospecificity) or for Fc and additional self antigens (polyreactivity) was found to correlate with the expression of specific heavy chain associated idiotypes. The VH3 associated RF idiotypes, D12 and B6, were expressed by 0/16 (0%) of monospecific RFs compared with 6/22 (27%) of polyreactive RFs. The predominant use of VH3 was verified by analysis of the expressed Ig with VH family specific anti-peptide antibodies. The light chains expressed by both populations of IgM RFs were found to be predominantly VKIII, both by detection of specific epitopes/idiotypes and V family analysis. This non-random gene usage of both the heavy and light chains suggests that there is a selective expression of V regions in the RF producing B-cells in patients with RA and SLE. We suggest that different antigen-driven, clonal selection events may occur which result in either monospecific RFs or polyreactive RFs.
Arthritis, Rheumatoid↗
Correlative studies of rheumatoid factors and anti-viral antibodies in patients with rheumatoid arthritis.
An analysis of the relationship between the immune response to ubiquitous herpes family viruses, namely Epstein-Barr virus (EBV), cytomegalovirus (CMV), and varicella-zoster virus (VZV) and the presence of rheumatoid factors (RF), which are autoantibodies characteristic of patients with rheumatoid arthritis (RA), was conducted. Antibody profiles (RF, anti-viral antibodies) were monitored in the serum of the RA patients, and in normal individuals. No patient was found to have circulating RF in the absence of anti-viral antibodies. When the patients and normal controls were subdivided according to the presence of serum RF, it was found that when RF were present, the frequency of anti-CMV antibodies, but not anti-EBV or anti-VZV antibodies, was significantly higher (P = 0.02) when compared with RF-negative individuals. The titres of anti-CMV but not anti-VZV antibodies were found to increase in the RA patients with disease duration. To see if these viruses could stimulate RF production in vitro, peripheral blood mononuclear cells (PBMC) isolated from the patients and normal controls were stimulated with viral antigens. PBMC from normal controls, but not from RA patients, appeared to be responsive to viral antigen stimulation and produced RF. These data suggest that the immune response to CMV, to a greater extent than to EBV or VZV, correlates with the presence of RF.
Adult↗