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P Ivanyi

Publications and source records attributed to P Ivanyi.

At least 19 recordsLinked to original sources
PubMed2006

Sexual dimorphism, but not testosterone itself, is responsible for ankylosing enthesitis of the ankle in B10.BR (H-2k) male mice.

BACKGROUND: Ankylosing enthesopathy (ANKENT) with progressive stiffening of ankle and tarsal joints of the hind limbs is a naturally occurring arthropathy in B10.BR mice. Some features are similar to those of the spondyloarthropathies in humans. OBJECTIVE: To study the role of sexual dimorphism and testosterone in the development of ANKENT. METHODS: The incidence of ANKENT was observed in non-castrated, castrated, and testosterone substituted castrated male mice, and in control and testosterone treated female mice. RESULTS: ANKENT occurred only in males; it did not develop in males castrated at age 2-3 months but occurred in castrated males injected with testosterone. Females injected with testosterone did not develop ANKENT. CONCLUSION: Testosterone can replace what castration eliminates, at least in the postpubertally castrated males, but is itself not sufficient to induce joint disease.

Animals↗
PubMed2001

The epitope recognized by pan-HLA class I-reactive monoclonal antibody W6/32 and its relationship to unusual stability of the HLA-B27/beta2-microglobulin complex.

A broadly used pan-HLA class I-reactive monoclonal antibody W6/32 is believed to recognize a conformational epitope dependent on association between heavy chains and beta2-microglobulin (beta2m). However, in the present study we report that W6/32 does recognize at least some free HLA class I heavy chains under the partially denaturating conditions of nonreducing Western blotting, namely nearly all HLA-B allelic products. Furthermore, we confirm and largely extend our previous observation that complexes of beta2m with heavy chains of a few HLA class I allelic forms (most notably HLA-B27) exhibit unusual resistance to dissociation by SDS, which is reminiscent of MHC class II molecules. In addition, our data indicate the existence of covalent (disulfide-linked) heterodimers of certain HLA class I heavy chains (namely Cw1 and Cw4) and beta2m.

Animals↗
PubMed2000

Germ-free mice do not develop ankylosing enthesopathy, a spontaneous joint disease.

Ankylosing enthesopathy (ANKENT) is a naturally occurring joint disease in mice with numerous parallels to human ankylosing spondylitis (AS). Similarities between AS and ANKENT include not only affected tissue (joint entheses) but also association of the disease with genetic background, including MHC genes, gender, and age. Young males with the C57Bl/10 background have been described to suffer from ANKENT and, among H-2 congenic strains, high frequency of afflicted joints has been recorded in B10.BR (H-2(k)) males. Interestingly, the incidence of ANKENT is higher in conventional (CV) males that in their specific-pathogen-free (SPF) counterparts. The latter finding suggests that microbes could play a role as an ANKENT-triggering agent. To further examine this hypothesis we have established a germ-free (GF) colony of B10.BR mice and observed ANKENT incidence in both GF males and their conventionalized (ex-GF) male littermates; 20% of ex-GF males developed ANKENT before 1 year of age. In contrast, no joint disease was observed under GF conditions (p < 0.0001). Our results show that live microflora is required in ANKENT pathogenesis.

Animals↗
PubMed2000

Strong association of HLA-B27 heavy chain with beta 2-microglobulin.

Monoclonal antibody TG1 recognizes specifically antigens HLA-B27, B7, B22 and B17 on cell surface in cytotoxicity and cytofluorometry tests. When cell detergent extracts were subjected to SDS PAGE under mild conditions (no heating and no reduction of the sample) followed by Western blotting, TG1 detected exclusively a complex of B27 heavy chains with beta(2)-microglobulin (as a 50 kDa band) whereas the other B-locus antigens (B7, B22, B17) were detected as free 43 kDa heavy chains under the same conditions. When the samples were boiled prior to SDS PAGE, TG1 detected again the 43 kDa free heavy chains of B7, B22 and B17 but no zone corresponding to B27 could be detected indicating that the epitope in free B27 chains is more sensitive to denaturation by SDS. Thus, our main finding is that the interaction of HLA-B27 heavy chain with beta(2)-microglobulin appears to be stronger than that of the other HLA-B chains. The resistance of the HLA-B27/beta(2)-microglobulin complex to the SDS dissociation is strikingly similar to the behavior of MHC class II molecules under similar conditions. Thus, it may be speculated that HLA-B27 complexes can be also more stable than other MHC class I molecules under more physiological dissociative conditions (e.g. in endosomal compartments). This feature might potentially influence antigen presentation by HLA-B27 and contribute to the well known disease linkage of HLA-B27.

Animals↗
PubMed1998

Preservation of immunological and colony-forming capacities of long-term (15 years) cryopreserved cord blood cells.

BACKGROUND: Cryopreserved cord blood may be stored for decades before being used for allogeneic stem cell transplantation. Little is known about the effect of long-term cryopreservation in liquid nitrogen on the viability and function of cord blood cells. We examined the recovery, viability, clonogenic capacity, and T-cell reactivity to HLA alloantigens of cord blood samples cryopreserved up to 15 years. METHODS: Progenitor cell recoveries were studied by (colony-forming unit-granulocyte-macrophage) clonogenic assays from 18 cord blood samples short-term frozen for 2-8 weeks and from 8 samples cryopreserved for 15 years. Proliferative and cytotoxic responses against HLA antigens of thawed cord blood mononuclear cells after short-term or long-term cryopreservation were tested in standard mixed lymphocyte cultures and cell-mediated lympholysis assays. RESULTS: After thawing, the mononuclear cell recovery from long-term frozen cord blood low-density fractions averaged 80% (range, 64% to 92%). The presented data show that long-term frozen cord blood cells keep their clonogenic potential. No damaging effect was seen on the proliferative and cytotoxic capacities of long-term frozen cord blood T cells. CONCLUSIONS: The results support the possibility of long-term storage of progenitor cells from umbilical cord blood for future bone marrow reconstitution.

Blood Cells↗
PubMed1998

Histopathology of murine ankylosing enthesopathy.

Ankylosing enthesopathy is a spontaneously occurring progressive stiffening of the ankle and/or tarsal joints in mice of C57Black background. In C57BL/10 mice and mice of the same genetic background that had been made transgenic for HLA-B27, the start of the disease was detected by weekly testing for decreased mobility in the ankle/tarsus region. Ankylosing enthesopathy was found to begin with a short phase of proliferative inflammation of the joints and adjacent tissues, with some fibrinous exsudation, some leucocytic infiltration and slight bone erosion. This inflammation is soon accompanied and followed by proliferation of cartilaginous cells at the bone insertions of joint capsule ligaments (entheses). Ossification of the cartilage proliferations and some desmal ossification lead to large osteophytes that inhibit mobility. Fusion of osteophytes occasionally leads to marginal ankylosis. The histopathology of the successive stages of murine ankylosing enthesopathy and the preponderance in males and HLA-B27 transgenic mice are reminiscent of ankylosing spondylitis in man. The spine, however, was not affected.

Animals↗
PubMed1997

The role of MHC class I heterodimer expression in mouse ankylosing enthesopathy.

Ankylosing enthesopathy (ANKENT) is a spontaneous mouse joint disease with strikingly similar pathology to human HLA-B27-associated enthesopathies such as ankylosing spondylitis. In C57Bl/10 mice, transgenic HLA-B*2702 as well as H2 genes have been shown to be relative risk factors for ANKENT. To investigate the role of major histocompatibility complex (MHC) class I expression in disease pathogenesis, ANKENT occurrence was compared among beta2-microglobulin (beta2m) knockout littermates with or without transgenes for HLA-B*2702 and human beta2m. In the knockout phenotype lacking beta2m, ANKENT occurrence is significantly reduced (P = 0.016). In the absence of beta2m, B*2702 is not detected on the cell membrane, nor does it increase the risk for ANKENT. This means that the previous finding that HLA-B*2702 increases susceptibility to ANKENT in C57Bl/10 mice cannot be ascribed to a transgene insertion effect. Rather, in order to increase disease susceptibility, B*2702 must be coexpressed with mouse beta2m (mo-beta2m). In contrast, when HLA-B*2702 is expressed with beta2m of human origin, disease susceptibility is not affected. Thus, both H2(b)-derived class I heterodimers and HLA-B*2702/mo-beta2m heterodimers contribute to ANKENT susceptibility.

Animals↗
PubMed1996

Solitary caging protects mice from ankylosing enthesopathy.

Murine ankylosing enthesopathy (ANKENT) is a spontaneous joint disease with numerous parallels to the human seronegative spondylarthropathies at the level of disease distribution, genetics and pathology. Although several genetic susceptibility factors have been identified previously, there is variation in disease susceptibility among genetically identical individuals, living in a stable environment. Preliminary observations indicate that males housed together with females rarely develop the disease, in contrast to males housed with other males (p < 0.25, p < 0.05, and p < 0.01). Furthermore, males caged under solitary conditions developed no ANKENT, whereas the disease did develop among individuals housed in groups of 4 (p < 0.01). The mechanism through which grouped caging induces a risk for ANKENT requires further study.

Animal Husbandry↗
PubMed1996

Grouped caging predisposes male mice to ankylosing enthesopathy.

OBJECTIVE: To evaluate the number of males per cage as a possible risk factor for murine ankylosing enthesopathy (ANKENT)--a spontaneous joint disease with parallels to human seronegative spondylarthropathies--since ANKENT shows incomplete penetrance of genetic susceptibility factors among individuals living in a stable environment. METHODS: Frequency of ANKENT was compared among males housed with females, with other males, or alone. RESULTS: In three independent cohorts, a trend was observed that males housed with females rarely develop the disease, in contrast to males housed with other males (P < 0.25, P < 0.05, and P < 0.01). Furthermore, no males caged alone developed ANKENT, whereas disease did occur in males grouped together (P < 0.01). When healthy males (retired breeders) were recaged either alone or with other males, ANKENT developed among the grouped males only (P < 0.005). CONCLUSIONS: Caging males together is a relative risk factor for ANKENT. Grouped caging may perturb the immune system through endocrine pathways or modify microbiological load through behaviour (for example, infection due to biting).

Animals↗
PubMed1995

Estimates of cytotoxic T-lymphocyte precursor frequencies against HLA class I antigens in responder-stimulator pairs with a negative mixed lymphocyte culture reaction.

Functional studies of helper and cytotoxic T cells in families with recombinant HLA haplotypes have played a crucial role in the early studies of the HLA chromosomal region. It has been shown that for the generation of CTLs directed against HLA-A or -B antigen differences an additional difference in the HLA-D region between responder and stimulator cells was a prerequisite. We have re-examined in a sensitive limiting dilution assay the possibility of generating CTL against HLA class I antigens in responder-stimulator pairs with a negative MLC reaction of two recombinant families (differing in one or two HLA class I antigens but identical in class II antigens) and two pairs of unrelated individuals. In all cases we could detect low but definitely measurable CTL activity (8-15 CTL precursors in 10(6) PBMCs) directed against the mismatched class I HLA antigen(s). We conclude that mismatches in class I HLA antigens in MLC nonreactive responder-stimulator pairs can induce generation of allospecific CTLs. This has implications in allogeneic bone marrow transplantation with HLA-matched unrelated donors; i.e., in the case of an HLA-A,B,DR matched donor a low donor CTLpf against the recipient may be an indication of a serologically not-detected class I HLA "subtype" incompatibility which might cause graft-versus-host disease.

Cytotoxicity Tests, Immunologic↗
PubMed1995

Maternal age influences risk for HLA-B27 associated ankylosing enthesopathy in transgenic mice.

OBJECTIVE: To study further the temporal clustering of ankylosing enthesopathy (AE) noted originally during a study of the influence of mouse major histocompatibility complex (MHC) H-2 and transgenic HLA-B27 on the frequency of AE. METHODS: The relationship between maternal age at littering and frequency of AE was analysed. RESULTS: Mice born to mothers aged eight months or older had a significantly lower disease frequency of AE than mice born to mothers younger than eight months of age. This phenomenon was observed in three independent cohorts evaluated to date (p < 0.01, 0.025, and 0.05). CONCLUSION: Maternal age is a novel, non-genetic risk factor as defined in relation to an MHC associated enthesopathy. Its mode of action and relevance to human disease require further investigation.

Animals↗
PubMed1993

Self-restricted primary human histocompatibility leukocyte antigen (HLA)-specific cytotoxic T lymphocytes.

The specificity of self MHC-restricted T cells responding to peptide fragments of processed antigen has been well characterized. However, the means by which alloreactive T lymphocytes recognize MHC alloantigen remain poorly understood. We now provide evidence that the recognition of class I human leukocyte antigen (HLA) alloantigen by alloreactive cytotoxic T lymphocytes (CTL) induced in primary mixed lymphocyte cultures is class I HLA-restricted to a great extent. This is shown by the 'split-well' limiting dilution assay using third party target cells bearing a stimulating class I HLA alloantigen either in (i) the presence or (ii) the absence of class I HLA antigen(s) which is shared with the responder. Alloreactive CTL were found which recognize stimulator class I HLA alloantigen on the first but not on the second type of target cells. The results show that, in contrast to the traditional view, a large proportion of the alloreactive CTL against class I HLA alloantigen generated in primary mixed lymphocyte cultures is self class I HLA-restricted.

Cells, Cultured↗
PubMed1993

Immunogenetics of the spondyloarthropathies.

In this review, recent data relevant to better understanding of the immunogenetics of the spondyloarthropathies are discussed or, in a somewhat broader sense, the HLA-B27 disease associations. Although in 1993 much more is known about the B27 molecule than was known in 1992, its contribution to the pathogenesis of disease is unclear. Peptide presentation to the T-cell receptor is still the basic, if not the only, function of HLA class I molecules. Nothing special was found for the B27 gene, molecule assembly, protein sequence, and crystal and peptide-binding motif, nor for the function dependent on these physical properties. Nevertheless, the theory regarding an "arthritogenic peptide" seemed to promise an explanation. However, this theory is rather an assembly of older views modified by the new data and is missing any detail or perspective that would answer the specific question: why B27 and not other HLA molecule(s)? If the solution is simple, and B27 is qualified to bind certain (bacterial) peptides that are not bound by any other class I molecule, or the unique complex, B27 + x, has special properties resulting in a "dysfunction," there is still no answer to the question: which peptide and why does its binding with B27 result in disease?

Animals↗
PubMed1992

Absence of autoantibodies to peptides shared by HLA-B27.5 and Klebsiella pneumoniae nitrogenase in serum samples from HLA-B27 positive patients with ankylosing spondylitis and Reiter's syndrome.

Some microorganisms which are pathogenic in humans share amino acid sequences with human proteins (molecular mimicry). It has been suggested that molecular mimicry might be a reason for autoimmunity as a result of immunological cross reactivity. A homologous sequence of six amino acids has been found in both Klebsiella pneumoniae nitrogenase and the HLA-B27.5 molecule. In addition, (auto)antibodies to a synthetic peptide that contained the HLA-B27.5/klebsiella mimicking epitope have been detected in serum samples from HLA-B27 positive patients with ankylosing spondylitis and Reiter's syndrome. Confirmation of these data is important, because ankylosing spondylitis and Reiter's syndrome have so far been assumed to be 'seronegative' rheumatic diseases. It was, however, not possible to confirm the presence of autoantibodies against the mimicking peptide in serum samples from patients with ankylosing spondylitis and Reiter's syndrome. Serum samples from 81 patients with ankylosing spondylitis, 38 patients with Reiter's syndrome, and 81 healthy blood donors were tested against the 'mimicking peptide' in an enzyme linked immunosorbent assay (ELISA). Some of the serum samples from patients showed high but non-specific binding to the mimicking peptide. A highly significant correlation between binding to plastic coated with the mimicking peptide, to plastic coated with an irrelevant peptide, and even to non-coated plastic was observed. The nature of the serum component(s) in these patient serum samples (and some control serum samples) responsible for the high non-specific binding to plastic remains unclear. It was also shown that antibodies to the HLA-B27 peptide (containing the mimicking epitope) induced in rabbits do not cross react with the klebsiella peptide and vice versa.

Adult↗
PubMed1992

H-2 influence on ankylosing enthesopathy of the ankle (ANKENT).

Joint disease, ankylosing enthesopathy (ANKENT) of the ankle, occurs naturally in mice. ANKENT depends on the genetical constitution, sex, and age, and its frequency varies among inbred strains of normal mice. We found the highest frequency of ANKENT in B10.BR (H-2k) males. The H-2k haplotype appears to be a relative risk factor, which increases the susceptibility to ANKENT. The aetiology of ANKENT is unknown but an involvement of microbial agents in the environment is supposed.

Animals↗