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N Manolios

Publications and source records attributed to N Manolios.

At least 37 records · Page 2Linked to original sources
PubMed1999

A Fas promoter polymorphism at position -670 in the enhancer region does not confer susceptibility to Felty's and large granular lymphocyte syndromes.

OBJECTIVE: We examined whether there are associations between a polymorphism in the Fas promoter, recently found to be associated with rheumatoid arthritis (RA), and Felty's syndrome or large granular lymphocyte (LGL) leukaemia. METHODS: Thirty-five patients with Felty's were studied, along with 18 patients with LGL syndrome and arthritis, 17 patients with LGL syndrome but no arthritis, and 128 controls. The polymorphism was typed by polymerase chain reaction followed by digestion with the restriction enzyme MvaI. RESULTS: No significant difference was found in genotype or allele frequencies between the groups. CONCLUSION: This promoter polymorphism is not a significant risk factor responsible for the LGL expansions seen in Felty's and LGL syndromes. Abnormal, constitutive expression of Fas ligand may be more relevant to the aetiology of these diseases.

Aged↗
PubMed1999

Familial risk estimation in systemic sclerosis.

BACKGROUND: Familial systemic sclerosis has been rarely reported. Assumptions have therefore been made implying no familial disease aggregation. This study critically challenges the assumption using a methodical population-based epidemiological approach to quantify the prevalence and characteristics of familial systemic sclerosis. METHODS: In this retrospective cohort study the systemic sclerosis prevalence in first degree family members was compared between 715 systemic sclerosis patients (710 families) and 371 randomly ascertained age and gender group-matched general practice controls (371 families). These data, obtained by telephone questionnaire (living patients) or medical records review (deceased patients and untraceable patients of unknown living status), were validated, where necessary, and expressed in terms of relative risk, absolute risk and population point prevalence. RESULTS: Systemic sclerosis affecting first degree members was validated in ten of 710 families. Reporting of systemic disease in another four more distant family members, and the co-occurrence of systemic and localised disease in three families was also documented. Observed and expected disease subtype concordance was 80% (44-97%) and 68% respectively and the female predominance among familial cases was similar to that for non-familial disease. The risk of disease in a subsequent first degree relative was compared to the risk in an initial first degree family member. Its estimated magnitude was wide (11-158). However, use of population prevalence data to determine the expected number of systemic sclerosis patients in the negative cohorts' families suggests the higher estimate is more realistic. Despite the high magnitude, the absolute disease risk in first degree family members remained low--approximating 1%. The population prevalence of familial systemic sclerosis approximated 1.4/million. CONCLUSIONS: This study substantially increases the otherwise small list of documented instances of familial systemic sclerosis. More importantly, it quantifies the risk for the first time, ranking it as the disease's most powerful determinant identified to date.

Cohort Studies↗
PubMed1998

The interchain disulfide linkage of T-cell antigen receptor-alpha and -beta chains is a prerequisite for T-cell activation.

Complementary DNAs encoding the T-cell antigen receptor (TCR)-alpha and mutant TCR-beta chains, lacking the interchain disulfide bond-related cysteine, were introduced into a TCR-alpha and -beta protein-deficient T-cell line. TCR-alpha and the mutant TCR-beta chains assembled with the CD3-epsilon, -gamma, -delta, and -zeta subunits and were efficiently transported to the cell surface; however, the hybrid TCR molecules exhibited a diminished response to T-cell activation by major histocompatibility complex-bound antigen, superantigen, and TCR cross-linking. These results suggest that the interchain disulfide bond between the TCR clonotypic chains is not required for TCR assembly and cell surface expression, but it plays an important role in maintaining the functional integrity of the TCR complex.

Animals↗
PubMed1997

Identification and characterization of polymorphisms in the promoter region of the human Apo-1/Fas (CD95) gene.

Apo-1/Fas (CD95) is a transmembrane protein expressed on the cell surface that is involved in apoptosis and plays an important role in the function and regulation of the immune system. Aberrant expression of the Apo-1/Fas gene product has been reported in a number of immune-related disorders, such as autoimmune lymphoproliferative syndrome and systemic lupus erythematosus in humans. Mutations in the coding sequence of the Apo-1/Fas gene have been reported in the former condition, whereas no abnormalities of the gene have been found to account for the increased gene expression noted in SLE. We screened the whole 5' flanking region of the Apo-1/Fas gene encompassing over 2000 bp for mutation(s)/polymorphism(s) using multiplex PCR, single-strand conformation polymorphism (SSCP) analysis and sequencing techniques, and identified two polymorphisms in this region. The first polymorphism is a CG-->CA substitution at -1377 nucleotide position within the silencer region, which neither creates or deletes any restriction enzyme sites but alters the transcription factor SP-1 binding site. This polymorphism is noted in 20% of normal Caucasians. The second polymorphism is an GA-->GG substitution at -670 nucleotide position in the enhancer region that creates a MvaI restriction fragment length polymorphism (RFLP) and abolishes the binding site of nuclear transcription element GAS. The MvaI RFLP is polymorphic with heterozygosity of 52% and the frequency of G and A alleles are 0.49 and 0.51, respectively. The identification and characterisation of these two new polymorphisms, particularly the MvaI RFLP marker, provides new genetic markers and may prove useful for further studies on the regulation of apoptosis mediated by the Apo-1/Fas gene on human chromosome 10q23.

Apoptosis↗
PubMed1997

T-cell antigen receptor transmembrane peptides modulate T-cell function and T cell-mediated disease.

This study describes a novel method of inhibiting T-cell function by the use of peptides rationally designed from the T-cell antigen receptor (TCR) alpha-chain transmembrane sequence involved with TCR receptor assembly. The most effective peptide (core peptide, CP) modulating in vitro and in vivo T-cell function contained nine amino acids two of which, lysine and arginine, were hydrophilic and separated by four hydrophobic amino acids. CP without chemical modification or conjugation was able to enter non-T and T cells. Conjugation of CP at the carboxyl terminus with palmitic acid resulted in a greater inhibition of T-cell interleukin-2 (IL-2) production in vitro than peptide alone. When examined for effects in vivo, CP reduced clinical signs of inflammation in three T cell-mediated disease models including adjuvant-induced arthritis, experimental allergic neuritis, and cyclophosphamide-induced diabetes in NOD/Lt(F) mice. This peptide or its analogues has potential as a therapeutic agent in human inflammatory and autoimmune disorders.

Amino Acid Sequence↗
PubMed1997

Lack of linkage between anti-nuclear antibody or clinical features of systemic lupus erythematosus (SLE) and TCR-A/Vbeta loci in families of subjects with SLE.

The role of the TCR-A and TCR-Vbeta genes in the genetic predisposition to SLE expression and anti-nuclear antibody (ANA) production were examined by linkage analysis in eighteen multiplex and forty-three simplex SLE families. All subjects were Caucasian. A significantly increased prevalence of positive ANAs in first-degree relatives of SLE patients from multiplex families was noticed compared to that of simplex families. Linkage between TCR-A/Vbeta genes and SLE expression and ANA production were analysed by affected sib-pair method. Results showed that the haplotypes identical by descent sharing TCR-A and TCR-Vbeta genes in the affected sib-pairs was not different from that expected (P = 0.93 and P = 0.74, respectively). There was no linkage between ANA positivity and TCR-A and TCR-Vbeta genes in ANA positive sib-pairs from both multiplex and simplex families. This study suggests that germline TCR-A and TCR-Vbeta gene loci confer no susceptibility to ANA and SLE expression.

Adult↗
PubMed1997

X-chromosome inactivation in monozygotic twins with systemic lupus erythematosus.

The hypothesis that a low concordance rate in monozygotic (MZ) twins with systemic lupus erythematosus (SLE) may be accounted for by differences in X-chromosome inactivation was examined. Five MZ twin pairs, four discordant and one concordant, were recruited, zygosity confirmed by DNA fingerprinting, and their pattern of X-chromosome inactivation in DNA samples prepared from peripheral blood and buccal cells were examined. X-chromosome inactivation was assessed by the methylation status of the CpG region near trinucleotide repeats in exon 1 of the androgen receptor gene on X-chromosome after digestion with the methylation-sensitive enzyme HpaII or HhaI and PCR amplification. X-chromosome inactivation patterns were found to be the same between affected and non-affected twins in all four discordant twin pairs, with random patterns in two pairs and skewed patterns in the others. The concordant twins demonstrated the same random patterns. X-chromosome inactivation was also examined from buccal smear DNA and shown to have the same pattern as that noted from peripheral blood DNA in one informative twin pair. Differences in X-chromosome inactivation patterns were not observed in these five MZ twin pairs. The results could not support the hypothesis that differences in X-chromosome inactivation is the mechanism accounting for the low concordance rate noted in MZ twins with SLE.

Adult↗
PubMed1997

Family and twin studies in systemic lupus erythematosus.

We have estimated how much of the total genetic predisposition to SLE may be attributable to genes outside the HLA region by comparing figures for concordance of SLE in monozygotic twins with those for concordance in HLA identical siblings in Australia. None of six dizygotic co-twins of white Australian SLE probands was concordant for SLE. One of four (25%) monozygotic co-twins of white Australian SLE probands was concordant for SLE which when added to previously published figures for Caucasoid populations gives an overall concordance rate for SLE in monozygotic twins of 25%. None of 18 HLA identical, same sex siblings of SLE probands, had definite SLE by the study criteria (i.e. less than 6%). The comparison of these figures shows that most of the genetic predisposition to SLE is attributable to genes outside the HLA region.

Adolescent↗
PubMed1996

Evaluation of the BCL-2 gene locus as a susceptibility locus linked to the clinical expression of systemic lupus erythematosus (SLE).

Systemic lupus erythematosus (SLE) is an autoimmune disease characterised by the production of a large number of autoantibodies. It has been postulated that this may be the result of prolonged longevity of auto-reactive B cells due to defective regulation of programmed cell death (apoptosis). The proto-oncogene bcl-2 is involved in the control of apoptosis in immunocompetent cells, and its over-expression is noted in T and B cells from SLE patients. This study examined the genetic linkage between the bcl-2 gene locus and SLE susceptibility using the affected sib-pair method in SLE families. Seventeen caucasian multiplex families were evaluated. A polymorphic microsatellite marker closely linked to the bcl-2 gene on 18q21.3 was used to determine the bcl-2 genotype. We demonstrated that haplotype sharing among the affected sibling pairs was not statistically different from random (P > 0.5). This suggests that the bcl-2 gene locus does not confer a genetic susceptibility to SLE expression.

Alleles↗
PubMed1996

Conformation of the T-cell antigen receptor-beta chain C-domain contributes to V beta 3 epitope recognition by monoclonal antibody KJ25.

The clonotypic T-cell antigen receptor (TCR)-beta chain contains two extracellular intrachain disulfide bonds. It belongs to the immunoglobulin gene superfamily and is subdivided into variable (V), joining (J), diversity (D) and constant (C) region. Monoclonal antibody (MoAb) KJ25 is believed to recognize an epitope in the V-domain of TCR-beta (V beta 3) chain, but its epitope requirements are unknown. In this study of TCR-alpha beta chain interactions using chimeric recombinant TCR-beta chains, the authors found that partial substitution of the C beta-domain with that of interleukin-2 receptor alpha chain (Tac) sequences led to the loss of TCR-V beta 3 epitope recognition by KJ25. These results suggest that epitope recognition of the TCR-V beta 3 by KJ25 MoAb is dependent not only on the V-domain, but also on the close contact with the extracellular C-domain which influences the conformation and epitope recognition of the V beta 3-region. This may not be unique to V beta 3 and may be a general feature of TCR-beta protein folding.

Animals↗
PubMed1996

Scleroderma and watermelon stomach.

Two patients with scleroderma (systemic sclerosis, SSc) and chronic blood loss secondary to gastric vascular ectasia--"watermelon stomach"--are presented. These cases exemplify the condition of gastric vascular ectasia and highlight the increasingly recognized association with autoimmune antibodies and connective tissue disease such as SSc. In both cases the onset of gastric blood loss coincided with the clinical manifestations of sclerodactyly by months, suggesting some temporal relationship. Although a number of different treatment modalities are available, and discussed in this report, both cases required gastrectomy.

Aged↗
PubMed1996

Structural mutations in the constant region of the T-cell antigen receptor (TCR)beta chain and their effect on TCR alpha and beta chain interaction.

The region responsible for T-cell receptor (TCR)alpha and beta chain assembly has previously been shown to reside in their extracellular domains. In an attempt to delineate further the structural requirements for TCR alpha and beta chain assembly, chimeric TCR beta chains with increasing length of constant (C) region and mutant TCR beta chains with C-domain point mutations were constructed. Their ability to assemble with wild-type TCR alpha chain was evaluated in non-T (COS cells) or T cells. The results reveal that the C beta domain is the binding region to TCR alpha chain, whereas the intact variable (V), diversity (D) and joining (J) regions with a short C-domain of beta chain are not sufficient for the TCR alpha and beta chain assembly. The unique interchain disulphide bond between TCR alpha and beta chains is not required for the TCR alpha beta heterodimer formation.

Base Sequence↗
PubMed1995

The T cell antigen receptor beta chain interacts with the extracellular domain of CD3-gamma.

Selective pairwise interactions between a number of CD3 chains and the clonotypic T cell antigen receptor (TCR-alpha, -beta) chains have recently been reported. What still remains unanswered is the site of interaction between TCR-beta and CD3-gamma chains. To examine the region of interaction between TCR-beta and CD3-gamma chains, a variety of genetically altered TCR-beta and CD3-gamma chains were constructed using recombinant cDNA techniques. Non-T cells (COS-7) were transfected with cDNA constructs, metabolically labelled, and immunoprecipitates were analysed for assembly using non-equilibrium pH gel electrophoresis (NEPHGE)/SDS-PAGE. The results demonstrated that assembly between TCR-beta and CD3-gamma chains was localized to their extracellular domain. These findings, when coupled with the information on pairwise interactions and formation of higher order subcomplexes, extend our model of the structure of the TCR complex.

Antigens, Differentiation, B-Lymphocyte↗
PubMed1995

Hierarchy of T cell antigen receptor assembly.

The formation of partial complexes in an African green monkey kidney cell line (COS cells) has been used to examine assembly of newly synthesized T cell antigen receptor (TCR) chains. The identification of assembly interactions between multiple subunits and the formation of higher order subcomplexes has led to the development of a model for the hierarchy of subunit assembly leading to a complete TCR. These assembly interactions suggest likely nearest neighbour relationships in the assembling structure and probably reflect the quarternary structure of the TCR complex. This may be important when examining the association of other molecules with TCR proteins or when trying to discern structural components involved with signal transduction.

Animals↗
PubMed1995

Immunogenetic analysis of 5 families with multicase occurrence of scleroderma and/or related variants.

OBJECTIVE: To investigate the relative contribution of the major histocompatibility (MHC) gene complex in the etiopathogenesis of familial scleroderma and/or its variants, in 5 Australian families, each with 2 affected members. METHODS: Affected individuals and consenting first degree relatives were examined and had blood collected for histocompatibility leukocyte (HLA) class I, class II antigen, and complement C4 typing. An antinuclear (ANA) profile screen on each family member was performed. RESULTS: Family 1, had 2 affected siblings (scleroderma, CREST), each anticentromere positive (> 1/640 titer), with identical HLA haplotypes. A brother, who was HLA identical to his affected sisters was clinically normal and ANA negative. In Family 2, there were no HLA haplotype similarities between the 2 sisters affected with diffuse scleroderma. Both were ANA positive (> 1/640). A 3rd sister was HLA identical to the proband but was clinically normal and ANA negative. In Family 3, affected siblings (CREST, morphea) had identical HLA haplotypes. In Family 4, both mother (CREST) and one of her 2 daughters (scleroderma) had anticentromere antibodies (1/2560). The unaffected daughter, not sharing either of her sister's haplotypes, was normal and ANA negative. In Family 5, 2 sisters (CREST, CREST) were HLA identical. CONCLUSION: A female predominance in familial scleroderma was observed. There was no common HLA haplotype between different families affected with scleroderma or its disease variants. Within families (except in one case, where the possibility of crossover exists or a question of paternity) affected siblings shared both HLA haplotypes. The development of disease was not totally accounted for by HLA genes, since family members with the same HLA haplotypes as the proband, were not affected. It appears that genes within the MHC complex are required but are not sufficient for the development of systemic sclerosis.

Adolescent↗
PubMed1994

The T cell antigen receptor alpha and beta chains interact via distinct regions with CD3 chains.

Selective pairwise interactions between CD3 chains and the clonotypic T cell antigen receptor (TCR)-alpha, -beta chains has recently been established. In this study, the region of interaction between clonotypic and CD3 chains involved with assembly was examined. To determine the site of protein interaction a variety of genetically altered TCR chains were constructed. These included: truncated proteins, lacking transmembrane and or cytosolic domains; chimeric proteins, in which extracellular, transmembrane or cytosolic domains were replaced with similar domains derived from either the Tac antigen or CD4; and point mutagenized TCR chains. COS-1 cells were transfected with cDNA, metabolically labeled, and immunoprecipitates analyzed using non-equilibrium pH gel electrophoresis (NEPHGE)-SDS/PAGE. The results demonstrated that assembly between TCR-alpha and TCR-beta chains occurred at the extracellular level. Assembly of the TCR-alpha chain with CD3-delta, and CD3-epsilon was localized to an eight-amino acid motif within the transmembrane domain of TCR-alpha. Site-specific mutations of the TCR-alpha charged residues within this motif (arginine, lysine) to leucine and similar point mutations of the transmembrane CD3-epsilon and CD3-delta charge groups resulted in the abrogation of assembly. In contrast, TCR-beta and CD3-epsilon binary complexes interacted via their extracellular domain. Analogous to TCR-alpha, the site of TCR-beta and CD3-delta assembly was at the transmembrane region. Despite multiple genetic manipulations on CD3-gamma and zeta these proteins failed to assemble with TCR-alpha. Similarly, there was no interaction between TCR-beta and zeta. These findings when coupled with the information on pairwise interactions and formation of higher order subcomplexes extend our model for the structure of the TCR complex.

Animals↗