Biomedical subjects
J B Harley
Publications and source records attributed to J B Harley.
Genes for murine Y1 and Y3 Ro RNAs have class 3 RNA polymerase III promoter structures and are unlinked on mouse chromosome 6.
Murine YRNAs, which are components of the conserved Ro ribonucleoprotein (RNP) complex, have been identified by enzymatic RNA sequencing. Mouse Y1 (mY1) and Y3 (mY3; originally named mY2) RNAs share 97 and 95% identity to the human Y1 and Y3 RNAs, respectively. TATA-like sequences, Proximal Sequence Elements, and octamer sequences, which are upstream promoter element motifs indicative of Class 3 RNA Polymerase III (RNAPIII) transcribed genes, are found upstream of both the putative mY1 and mY3 coding regions. Further, these elements are strikingly conserved both in sequence and position relative to known Class 3 genes and to human YRNA genes. Inhibition of transcription in vitro by 200 micrograms/ml but not 1 microgram/ml of alpha-amanitin indicates transcription of the mouse YRNA genes by RNAPIII. Southern blot of C57BL/6J and Mus spretus murine genomic DNA with mY1 and mY3 gene-specific probes suggests that these genes are single copy in the mouse genome. Finally, gene mapping with a (C57BL/6J x SPRET/Ei)F1 x SPRET/Ei mouse interspecific backcross DNA panel localizes the mY1 gene to the distal end of mouse chromosome 6, close to the motheaten (me) autoimmunity locus. The mY3 gene maps to the proximal end of mouse chromosome 6 very close to the T cell receptor beta locus, in a region homologous to human chromosome 7 where the human YRNA genes have been mapped.
Human lupus anti-spliceosome A protein autoantibodies bind contiguous surface structures and segregate into two sequential epitope binding patterns.
High levels of anti-spliceosomal autoantibodies are commonly found in systemic lupus erythematosus (lupus) sera. We have evaluated the binding of lupus autoantibodies to octapeptides of nuclear ribonucleoprotein (nRNP) A, identified patterns of binding that vary between sera, quantified the proportion of anti-nRNP that binds individual peptides, and related these data to the partial tertiary structure of nRNP A. Anti-nRNP A-positive lupus sera share binding to eight antigenic groups of octapeptides from nRNP A. The four shared antigenic sites in the known nRNP A tertiary structure are contiguous on its surface and include surface loops between beta sheets and/or alpha helices. Anti-peptide Abs account for a significant portion of the human autoimmune response to nRNP A. Lupus sera are also obviously divisible into two subsets by their binding to nRNP A-derived peptides. Eight of the thirteen anti-nRNP A sera tested bind most of the eight common antigenic regions of nRNP A. All five sera in the other subset bind to two and only two groups of nRNP A octapeptides. Of this subset, absorption experiments show that as much as 75% of the anti-nRNP found in a patient serum is bound to these two octapeptides from nRNP A. The 70K spliceosome protein contains similar peptides that are also bound by these sera (OR=13.5, p<0.001). Lupus autoantibodies bind to peptides of nRNP A in discernibly consistent patterns that identify serologic subsets and in a manner that provides useful insights into the autoimmunity and antigenic structure of the nRNP A spliceosomal protein.
Immunization with short peptides from the sequence of the systemic lupus erythematosus-associated 60-kDa Ro autoantigen results in anti-Ro ribonucleoprotein autoimmunity.
Systemic lupus erythematosus is characterized by the production of Abs to ribonucleoproteins, including Ro (or SS-A) and La (or SS-B). The mechanism by which these autoantibodies arise is unknown. We have immunized rabbits with peptides from the sequence of the 60-kDa Ro. Animals so immunized not only produce Abs to the immunogen peptide, but also develop an autoimmune response to the entire 60-kDa Ro Ag. In about 20% of these animals, autoimmunity also spreads to the La Ag. Anti-native DNA was present in one of nine rabbits. All animals had anti-nuclear Ab, but even among those immunized with the same peptides, different patterns of immunofluorescence were found. Thus, among these outbred animals immunized with peptides from 60-kDa Ro, distinct serologic manifestations were present, showing heterogeneity in the development of autoimmunity.
Rheumatoid arthritis in a United States Public Health Service Hospital in Oklahoma: serologic manifestations in rheumatoid arthritis vary among tribal groups.
OBJECTIVE: To study the serologic manifestations of rheumatoid arthritis (RA) at a United States Public Health Service Hospital that serves numerous tribes in Oklahoma. METHODS: Forty-five patients with RA were identified, and serologic studies for antinuclear antibody (ANA), rheumatoid factor, and antibodies to extractable nuclear antigens were performed. Extraarticular manifestations of RA were also evaluated. RESULTS: Twelve of the 45 patients with RA were Kiowa. These patients were significantly more likely to have a positive ANA (75%) than the other patients with RA (28%). In addition, anti-Ro was significantly more common among Kiowa (33%) than among members of other tribes (3%). There was no difference in the extraarticular manifestations of the Kiowa compared with the other Native American tribes. CONCLUSION: RA can be distinctly characterized by serology among groups of American Indians living in the same geographic area.
Development of the anti-Ro autoantibody response in a patient with systemic lupus erythematosus.
OBJECTIVE: To characterize the initial events in anti-Ro production by a patient with systemic lupus erythematosus, in whom this autoantibody is developing. METHODS: The immune response to the Ro ribonucleoprotein and other autoantigens were studied by enzyme-linked immunosorbent assay for IgG and IgM, by isoelectric focusing, and by inhibition studies to determine apparent avidity. RESULTS: The patient's sera showed an oligoclonal response to Ro that increased in complexity and affinity with time. IgM anti-Ro appeared shortly before IgG anti-Ro, and disappeared as IgG anti-Ro increased in titer and affinity. IgG antiribosomal P autoantibodies also appeared during the patient's course, but in contrast to anti-Ro, were not preceded by IgM antiribosomal P. CONCLUSION: These data are consistent with the Ro autoantigen being presented and processed in a manner similar to heterologous antigen, and with differences in the mechanisms that lead to the production of IgG anti-Ro autoantibodies as opposed to antiribosomal P autoantibodies.
The recognition of human 60-kDa Ro ribonucleoprotein particles by antibodies associated with cutaneous lupus and neonatal lupus.
The hY RNAs form a macromolecular complex with the 60-kDa Ro protein and may in addition be bound by the La protein. In this study, we examine the autoantibody responses to the intact protein-RNA complexes in 18 subacute cutaneous lupus (SCLE), 10 discoid lupus (DLE), and 18 neonatal lupus erythematosus (NLE) sera. All SCLE and NLE serum samples precipitated all four of the Ro hY RNAs, whereas none of the DLE serum samples precipitated the hY RNAs. Among the SCLE and NLE sera, there was a significant association between the amount of Ro hY RNAs precipitated and the concurrent presence of anti-La antibodies in the sera (p = 0.008), consistent with the hypothesis that both the 60-kDa Ro and the La proteins can bind the Ro hY RNAs. There was no correlation between the amount of hY RNAs precipitated and the titer of antibodies to the 60-kDa Ro protein in enzyme-linked immunosorbent assay (ELISA). This may be due to a difference in the epitopes formed by the antigen in the respective assays. The autoantibody response to Ro in SCLE and NLE, which is generally detectable by both immunodiffusion and ELISA, is directed to all the subsets of the Ro protein-hY RNA complexes. The autoantibody response in DLE, though frequently detectable by ELISA, is not of sufficient concentration or affinity to precipitate the Ro protein-RNA complexes. The autoantibody response to Ro in SCLE and NLE may include antibodies to epitopes created by the complexing of the 60-kDa Ro protein with hY RNA.
The spectrum of ankylosing spondylitis.
Sacroiliac involvement is an early hallmark, but even so, patients with ankylosing spondylitis present a remarkable spectrum of disease. Research probing associations among spondylitis, enteric bacterial infection, and host expression of HLA-B27 may offer etiologic clues and point the way to disease-specific therapies.
HLA-B27 binding of peptide from its own sequence and similar peptides from bacteria: implications for spondyloarthropathies.
The spondyloarthropathies are associated by an unknown mechanism with HLA-B27 and certain bacteria. HLA-B27 shares sequence with proteins from enteric bacteria. The B*2705 sequence contains a nonapeptide, LRRYLENGK, predicted to bind in the binding cleft of B27. Some nonapeptides from enteric organisms that share sequence with this nonapeptide of B27 also bind B27. These observations suggest an unappreciated mechanism for autoimmunity that may operate in the B27-associated spondyloarthropathies involving peptides bound to and derived from histocompatibility alleles.
Y3 is the most conserved small RNA component of Ro ribonucleoprotein complexes in vertebrate species.
YRNAs are small cytoplasmic RNAs that are components of the Ro ribonucleoprotein complex. This complex, which also includes the 60-kDa Ro protein, is a human autoantigen which is conserved among vertebrates, and is of unknown function. Multiple sequences with YRNA homology, known as YRNA-like sequences, have been detected in rabbit, mouse, duck, iguana and frog genomes with human Y cDNA probes. As judged by Northern blots of total RNA, however, not all of these genomic YRNA-like sequences are expressed. Complementary DNA and putative gene sequences for iguana Y3 (iY3) and iguana Y4 (iY4) Ro RNAs have been determined and used, along with previously sequenced human and frog Ro YRNA sequences, to construct the most likely Y3 and Y4 RNA secondary structures. The data presented indicate that Y3 is the most conserved Ro RNA, not only by its more consistent presence in other species, but also at the levels of sequence divergence and secondary structure similarity. The differences observed between the secondary structure solutions for the Y3 and Y4 Ro RNAs are consistent with the possibility that these RNAs perform different cellular functions.
Immunoglobulin epitope spreading and autoimmune disease after peptide immunization: Sm B/B'-derived PPPGMRPP and PPPGIRGP induce spliceosome autoimmunity.
Autoantibodies from many patients with systemic lupus erythematosus bind the Sm autoantigen B/B' polypeptide. The binding of serial serum specimens to the 233 overlapping octapeptides of Sm B/B' have shown that of the B/B'-derived octapeptides, PPPGMRPP and PPPGIRGP are early targets of the autoimmune response in some lupus patients. Rabbits immunized with PPPGMRPP and PPPGIRGP develop antibodies which not only bind these octapeptides, but also subsequently bind many other octapeptides of Sm B/B'. Eventually, the rabbits immunized with one octapeptide develop autoantibodies that bind other spliceosomal proteins including D, 70K, A, and C. Any mechanisms that operate to maintain tolerance or anergy for the spliceosome are thus overcome. Features considered typical of human systemic lupus erythematosus are also found in these peptide-immunized animals, such as antinuclear antibodies, anti-Sm precipitins, anti-double-stranded DNA, thrombocytopenia, seizures, and proteinuria. This disease model provides access to a mechanism for the development of humoral autoimmunity and may provide a basis to explain the immunopathogenesis of lupus in humans.
Logistic transmission modeling of simulated data.
A nonparametric method for linkage analysis has been developed and applied to the Problem 1 data set of the Genetic Analysis Workshop 9. Basically, the univariate matched pair strategy of the transmission disequilibrium test has been adapted to multivariate modeling using the conditional logistic function. After setting the critical value for significance at p < or = 0.0001, models at only D5G23 and D1G31 appear to be significant (p < 10(-7)). Logistic transmission modeling is a powerful method for establishing linkage by disequilibrium.
Immunogenetics of epitopes of the carboxyl terminus of the human 60-kD Ro autoantigen.
Systemic lupus erythematosus is associated with the presence of autoantibodies which bind several ribonucleoproteins, including Ro (or SS-A). We have explored the relationship of the HLA-DQ and T cell receptor alleles in patients producing autoantibodies binding the 13-kD carboxyl terminus fragment of the 60-kD Ro and with autoantibodies binding a peptide epitope within this fragment (amino acid residues 480-494). Antibodies binding the 13-kD fragment are more likely to be found in the sera of patients with particular DQA1 and DQB1 alleles, while antibodies binding the epitope at 480-494 are found almost exclusively in the sera of patients with a Bg/II 9.8-kb polymorphism of the T cell receptor beta gene. Meanwhile, in these same patient sera the level of autoantibodies binding the complete 60-kD Ro particle is associated with a distinct pattern of alleles at these same immunoregulatory loci. These data demonstrate that component parts of autoantibody responses may be under genetic control which can be distinguished from the HLA associations characteristic of the response to the intact, complete autoantigen.
Human anti-Ro autoantibodies bind peptides accessible to the surface of the native Ro autoantigen.
The relationship between fine specificity of linear epitopes and conformational determinants has been explored in a naturally arising human autoimmune response. In particular, the hypothesis tested is that the linear epitopes of the human Ro autoantigen are components of its conformational epitopes. Twenty groups among the 531 overlapping octapeptides 60 kDa Ro are variably bound by anti-Ro precipitin positive lupus sera whose reactivity was easily distinguished from sera of normal controls and of anti-Ro precipitin negative lupus patients. The specific activities of anti-peptide antibodies and of anti-native Ro autoantibodies are similarly increased after affinity enrichment using native human Ro as ligand. Moreover, affinity-enriched anti-native Ro autoantibodies bind virtually the same 20 groups of epitopes recognized by whole anti-Ro positive sera. Two peptides (residues 274-290 and 480-494) from the defined 60 kDa Ro octapeptide epitopes have been prepared and used as ligands for affinity purification of peptide specific autoantibodies. The binding of both whole IgG and affinity-enriched peptide specific autoantibodies is inhibited by native Ro autoantigen. Thus, none of the available data can be construed to support the existence of cryptic linear epitopes in this system. Indeed, the data are only consistent with the conclusion that all of the anti-Ro octapeptide autoantibodies are part of the population of anti-native Ro autoantibodies in this naturally arising autoimmune response.
Immunization with vesicular stomatitis virus nucleocapsid protein induces autoantibodies to the 60 kD Ro ribonucleoprotein particle.
BACKGROUND: Systemic lupus erythematosus (SLE) is an autoimmune disorder of unknown etiology that is characterized by antibodies binding ribonucleoprotein complexes. The epitopes of SLE associated 60 kd Ro (or SSA) autoantigen share sequence with vesicular stomatitis virus (VSV) nucleocapsid (N) protein and SLE patients with anti-Ro are more likely to bind the N-protein than anti-Ro negative patients. METHOD: We immunized New Zealand white (NZW) rabbits with purified VSV N-protein to examine the relationship between the immune response to N-protein and anti-Ro. RESULTS: After multiple immunizations with VSV N-protein, NZW rabbits produced not only IgG antibodies to VSV N-protein but also an autoimmune response to Ro antigen. The IgG fraction of the rabbit immune serum precipitates 60 kd Ro protein as well as its associated Y RNAs. Antibodies elicited by 10 immunizations of VSV N-protein bind to at least 20 linear epitope groups on VSV N-protein and over 25 linear epitope groups on 60 kd Ro protein. These antibodies also bound 5 of the 6 shared sequences between 60 kd Ro protein and VSV N-protein. CONCLUSIONS: Our data demonstrate that an immune response initiated towards a foreign antigen, selected on the basis of sharing short sequence similarity with the autoantigenic epitopes of an autoantigen, can lead to an autoimmune response.
Association of anti-Ro/SS-A autoantibodies with glutamine in position 34 of DQA1 and leucine in position 26 of DQB1.
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Cooperative association of T cell beta receptor and HLA-DQ alleles in the production of anti-Ro in systemic lupus erythematosus.
The immunogenetics of the autoantibody response to Ro (or SS-A) have been explored in patients with systemic lupus erythematous. Data show that alleles of the T cell beta receptor and HLA-DQ loci are cooperatively associated with the presence of anti-Ro autoantibodies in systemic lupus erythematosus. Identification of HLA-DQ by oligonucleotide probe binding to polymerase chain reaction products demonstrates that the combination of DQB1*0201 and one of DQA1*0101, DQA1*0102, or DQA1*0103 is associated with anti-Ro. Patients possessing a particular pair of T cell receptor beta restriction enzyme polymorphisms along with these specific HLA-DQ alleles produce quantitatively more anti-Ro as measured by a sensitive solid-phase immunoassay than patients without these T cell receptor and DQ alleles. Other work has shown that the autoimmune response is directed against the human Ro antigen. These results are consistent with a central role in the disregulation of autoimmunity involving a trimolecular complex composed of the autoantigen bound by a HLA-DQ molecule which, together, are bound in turn by T cells which express a particular subset of T cell receptors.