Biomedical subjects

J Vives

Publications and source records attributed to J Vives.

At least 19 recordsLinked to original sources

PubMed2005

Novel MASP2 variants detected among North African and Sub-Saharan individuals.

The lectin pathway of the complement system is activated when mannan-binding lectin (MBL) in complex with MBL-associated serine protease 2 (MASP-2) binds to carbohydrate structures on microorganisms. Structural gene mutations and promoter polymorphisms in the MBL2 gene responsible for low-MBL serum levels are present in all human populations and associate with increased risk of infection. Recently, investigations on Danes revealed the existence of a mutation on the MASP2 gene, which introduces an amino acid substitution in the CUB1 domain (Asp105Gly; numbering refers to the mature protein), and is associated with reduction in the level of MASP-2 in serum. Here, we present the results of a sequence-based typing analysis of the MBL2 and MASP2 gene polymorphisms in a group of 65 Africans (50 North Africans and 15 Sub-Saharan) and of 104 Spaniards. The analysis identified three novel exon 3 MASP2 variants introducing amino acid substitutions at positions 84 (Arg-->Gln), 103 (Arg-->Cys) and 111 (Pro-->Leu) in the CUB1 domain. None of these variants were identified in Spaniards. The Arg84Gln was detected in four of the 15 Sub-Saharans. The Arg103Cys and Pro111Leu variants were detected only among North Africans (two and four individuals, respectively). The Asp105Gly variant was similarly represented among Spaniards and North Africans (three and two individuals, respectively), which appears to be a lower frequency than that reported for Danes (5.5%). As reported for MBL2, the marked geographic distribution of the new MASP2 variants may represent an evolutionary adaptation to different environments.

Africa South of the Sahara↗

PubMed2004

Biochemical characterization of recombinant and circulating human Spalpha.

Human Spalpha is a soluble protein expressed by macrophages present in lymphoid tissues (spleen, lymph node, thymus, and bone marrow), for which little functional and structural information is available. It belongs to the group B of the scavenger receptor cysteine-rich superfamily (SRCR-SF) that includes the lymphocyte surface receptors CD5 and CD6 among others. Spalpha is able to bind to different cells of the immune system (monocytes and lymphocytes), which suggests that it may play an important role in the regulation of this system. To study Spalpha, an episomal mammalian expression system (pCEP-Pu/HEK 293-EBNA) was used to produce a recombinant form (rSpalpha) that was utilized for biochemical studies and for the generation of specific hybridomas. Four monoclonal antibodies were selected for their reactivity against rSpalpha by Western blot, immunoprecipitation, and enzyme-linked immunosorbent assays. The monoclonal antibodies recognized three different epitopes on Spalpha. The monoclonal antibodies revealed the existence of two Spalpha isoforms of 38 and 40 kDa, resulting from different sialic acid content. They also showed that Spalpha is a relatively abundant serum protein (60 micro g/ml) that mostly circulates in association with other serum proteins. Accordingly, rSpalpha allowed affinity chromatography isolation of polyclonal and monoclonal immunoglobulin M (IgM). These data indicate that Spalpha is a circulating protein that may play a role in the homeostasis of IgM antibodies.

Antibodies, Monoclonal↗

PubMed2004

Description of a novel HLA-DRB1 allele found in a candidate for bone marrow transplantation.

We report the identification of a new DRB1* allele in a Spanish Caucasoid family during a search for a histocompatible bone marrow donor. This novel allele, designated as DRB1*1145, differs from DRB1*1123 in one nucleotide at position 199 in exon 2 (A replacing T), leading to one amino acid change from phenylalanine (Phe) to isoleucine (Ile) at codon 67. The propositus's father had identical class II alleles but showed a minor mismatch at locus B (B*4403 by B*4402) and a C-locus mismatch (Cw*1502 by Cw*0501). We discuss the criteria of selecting a non-related bone marrow donor with a minor mismatch on the DRB1* allele or the related father having a minor mismatch at B locus and a C-locus mismatch.

Alleles↗

PubMed2003

Characterization of a new HLA-C allele: Cw*1606.

HLA-Cw*16 is a relatively common HLA-C specificity among Caucasoids, with Cw*1601 being the most frequent allele. We report herein the identification by sequence-based typing of a new HLA-Cw*16 allele in a Spanish Caucasoid blood donor. The novel allele, designated Cw*1606, differs from Cw*1601 by two nucleotide changes at positions 361 (T to A) and 368 (A to C) in exon 3, which leads to two amino acid changes from Trp (TGG) to Arg (AGG) and from Tyr (TAT) to Ser (TCT) at codons 97 and 99 in the alpha2 domain, respectively. Sequence comparisons suggest that the new HLA-Cw*1606 variant could have arisen from an intralocus gene conversion event.

Alleles↗

PubMed2003

HLA-B*5130, a new HLA-B allele carrying a rare nucleotide substitution in exon 4.

We report herein the identification of a new HLA-B*51 allele in a Spanish Caucasoid organ donor. The novel allele, designated B*5130, differs from B*51011 by one nucleotide change at position 787 (A to G) in exon 4, leading to an amino acid change from Arg (AGA) to Gly (GGA) at codon 239 in the alpha3 domain. This substitution is present in most classical and nonclassical HLA class I loci (A, C, E, and G) but not in any of the HLA-B alleles reported so far, except for B*7301. Although the frequency of the new variant seems to be low, its existence makes mandatory the analysis of exon 4 before assigning a B*5101 type.

Alleles↗

PubMed2003

Anti-chromatin antibodies in systemic lupus erythematosus: a useful marker for lupus nephropathy.

BACKGROUND: Anti-chromatin antibodies have recently been described in patients with systemic lupus erythematosus (SLE) and it has been suggested that their presence is associated with lupus nephritis. OBJECTIVE: To assess the prevalence and clinical associations of these antibodies in SLE. METHODS: The presence of anti-chromatin antibodies in 100 patients with SLE was investigated by an enzyme linked immunosorbent assay (ELISA). To determine the specificity of these antibodies, 100 patients with primary Sjögren's syndrome, 30 with primary antiphospholipid syndrome (APS), 10 with systemic sclerosis, and 100 normal controls were also tested. RESULTS: Positive levels were detected in 69/100 (69%) patients with SLE. In contrast, they were found in only 8/100 (8%) of those with primary Sjögren's syndrome, in 1/10 (10%) with systemic sclerosis, in 2/30 (7%) with primary APS, and in none of the 100 healthy controls. Patients with anti-chromatin antibodies had a twofold higher prevalence of lupus nephropathy than those without these antibodies (58% v 29%, p<0.01). A significant correlation was found between the levels of anti-chromatin antibodies and disease activity score as measured by the European Consensus Lupus Activity Measurement (ECLAM; p=0.011). CONCLUSIONS: The measurement of anti-chromatin antibodies appears to be a useful addition to the laboratory tests that can help in the diagnosis and treatment of SLE. These antibodies are both sensitive and specific for SLE, and are a useful marker for an increased risk of lupus nephritis.

Adolescent↗

PubMed2003

[Congenital absence of the inferior vena cava as a risk factor for pulmonar thromboembolism].

The absence of the inferior vena cava is a rare congenital anomaly. Currently its diagnosis is based on non-invasive imaging techniques (computerised axial tomagraphy and nuclear magnetic resonance). In most cases, it constitutes a casual finding upon practising these image tests unrelated to this congenital anomaly. In the symptomatic patients, the complaints associated are secondary to venous insufficiency and/or deep vein thrombosis. Recently the congenital absence of inferior vena cava has been described as a risk factor of deep vein thrombosis in young patients. We present a case of congenital absence of inferior vena cava that was admitted in our hospital because of pulmonary thromboembolism.

Abnormalities, Multiple↗

PubMed2002

The role of interleukin-10 promoter polymorphisms in the clinical expression of primary Sjögren's syndrome.

OBJECTIVE: To analyse the role of polymorphisms of the interleukin-10 promoter region in the epidemiologic, clinical and immunologic characteristics of patients with primary Sjögren's syndrome (SS). METHODS: Sixty-three consecutive patients (59 women and four men; mean age 57 yr; range 20-83 yr) were studied in our Unit. All patients fulfilled four or more of the modified diagnostic criteria for SS proposed by the European Community Study Group in 1996. As controls, 150 healthy volunteers were recruited from the medical and laboratory staff working in our hospital. All the samples from patients and controls were analysed by PCR amplification and direct sequencing. RESULTS: The frequency of the interleukin-10 (IL-10) GCC haplotype was higher (0.48 vs 0.34, P=0.006) and the frequency of the IL-10 ACC haplotype lower (0.25 vs 0.39, P=0.005) in patients with primary SS compared with healthy controls. In the genotype analysis, the frequency of the GCC/ATA genotype was higher (29 vs 11%, P=0.001) and that of the ACC/ACC genotype lower (3 vs 12%, P=0.044) in patients with primary SS compared with healthy controls. GCC-carriers showed an earlier onset of the disease (48.06+/-14.98 yr vs 57.53+/-14.20 yr, P=0.034). The existence of systemic involvement (defined by cutaneous vasculitis, peripheral neuropathy, renal and/or pulmonary involvement) was more frequent in carriers of the GCC haplotype, although the difference did not reach statistical significance (40 vs 27%, P=0.278). No significant differences in the haematologic (hypergammaglobulinaemia, elevated ESR) and immunologic (ANA, RF, anti-Ro/SS-A and anti-La/SS-B antibodies) parameters were observed in carriers of the GCC haplotype. CONCLUSION: We describe an abnormal distribution of IL-10 promoter haplotypes in patients with primary SS compared with healthy controls. This consists of a predominance of the GCC haplotype, mainly related to a higher frequency of the heterozygote haplotype GCC/ATA. The presence of the GCC haplotype does not originate a different immunologic pattern but leads to an earlier onset of primary SS.

Adult↗

PubMed2001

Association of the cell cycle regulatory proteins p45(SKP2) and CksHs1. Functional effect on CDK2 complex formation and kinase activity.

In mammalian cells, CDK2 is part of a multiprotein complex that includes Cyclin A or E and cell cycle regulatory proteins such as p21(Cip1), PCNA, p27(Kip1), p45(SKP2), p19(SKP1), and CksHs1/CksHs2. While the role of some of these proteins has been well studied, the function of other proteins in the complex remains unclear. In this study, we showed that the carboxyl-terminal region of p45(SKP2) associates directly with CksHs1 and that CksHs1 negatively regulated the interaction between p45(SKP2) and CDK2. Moreover, we showed that overexpression of CksHs1 inhibits CDK2 kinase activity and that additional expression of p45(SKP2) overcame this inhibition and restored CDK2 kinase activity. We proposed that the association of CksHs1 and p45(SKP2) prevented CksHs1 from binding CDK2 and negatively regulating the CDK2 kinase activity.

Animals↗

PubMed2001

Role of two conserved cytoplasmic threonine residues (T410 and T412) in CD5 signaling.

CD5 is a transmembrane coreceptor that modulates activation and differentiation signals mediated by the Ag-specific receptor present on both T and B1a lymphocytes. CD5 lacks intrinsic catalytic activity, and its immunomodulatory properties result from intracellular interactions mediated by the CD5 cytoplasmic tail. The nature of these interactions is currently a matter of investigation. Here, we present a selective mutagenesis analysis of two conserved threonine residues (T410 and T412) located at the membrane-proximal cytoplasmic region of CD5. These residues are contained within consensus phosphorylation motifs for protein kinase C and are shown here to be critical for in vivo protein kinase C-mediated phosphorylation of CD5. Functional studies revealed that the integrity of T410 and T412 is also critical for CD5-mediated phosphatidylcholine-specific phospholipase C (PC-PLC) activation and phorbol ester-mediated inhibition of Ab-induced internalization of CD5. These results strongly argue in favor of a role for T410 and T412 in the signaling mediated by CD5.

Amino Acid Substitution↗

PubMed2001

Residues Y429 and Y463 of the human CD5 are targeted by protein tyrosine kinases.

The human CD5 lymphocyte cell surface co-receptor modulates activation and differentiation responses mediated by the antigen-specific receptor of T and B cells. CD5 is phosphorylated following lymphocyte activation; however, the exact sites and kinases involved are yet to be determined. Jurkat T cell transfectants expressing tyrosine-mutated CD5 molecules have been used to show that residues Y429 and Y463 are targeted in vivo by protein tyrosine kinases following cell stimulation with anti-CD3 mAb or pervanadate. This is in agreement with data from direct in vitro kinase assays using purified recombinant Lck and Fyn protein tyrosine kinases. The analysis of Lck- and CD3-deficient Jurkat cells shows that tyrosine phosphorylation of CD5 requires Lck activity. We propose that T cell activation mediates CD5 tyrosine phosphorylation at residues Y429 and Y463 mainly through the activation of Lck.

Amino Acid Substitution↗

PubMed2001

Identification of a novel single-nucleotide polymorphism (Val554Ile) and definition of eight common alleles for human IL4RA exon 11.

The interleukin (IL)-4 receptor alpha chain gene (IL4RA) is a polymorphic gene which is reportedly involved in the development of atopy. Of the 14 single-nucleotide polymorphisms (SNP) reported to date in the coding region of IL4RA, 11 are positioned to exon 11. This big exon encodes more than two thirds of the mature protein, including most of the cytoplasmic region. Here we report the identification of a new IL4RA SNP at the first nucleotide of codon 554 (GTA --> ATA) in exon 11, leading to an amino acid substitution from Val to Ile (V554I). Furthermore, we present complete nucleotide sequence data for eight common alleles resulting from combinations of 9 out of the 12 SNP at IL4RA exon 11. Homo- or heterozygous combinations of these eight alleles accounted for all the IL4RA exon 11 genotypes found in Caucasian individuals from our geographical area.

Alleles↗

PubMed2001

Identification of a new HLA-DRB1 allele (DRB1*0318) in three members of a Caucasian Spanish family.

This communication reports the identification of a new allele HLA-DRB1*03 in three members of a Caucasian Spanish family. The new allele has been officially named HLA-DRB1*0318 by the World Health Organization Nomenclature Committee. The exon 2 sequence of this new allele is identical to that of DRB1*03011 except for the first nucleotide of codon 45. The nucleotide change (C replacing G) leads to the amino acid substitution of glycine to arginine (GGG-->CGG) at position 45. This position of the beta1 domain shows very little polymorphism among DRB1* alleles (nucleotide changes at this position have only been reported for DRB1*1436 and DRB1*0105) and locates in the vicinity of the highly polymorphic position 47, which is a constituent of the groove's pocket interacting with the amino acid position 7 of the antigen peptide. The familial study showed that the new allele was maternally transmitted into the HLA-A*3002, -B*1801, -Cw*0501, -DRB1*0318, -DRB3*0202, -DQB1*0201 haplotype. Interestingly, the two siblings of the family, which were HLA identical and suffered of insulin-dependent diabetes mellitus (IDDM), were carriers of the two HLA haplotypes (DRB1*03/DQB1*0201 and DRB1*04/DQB1*0302) reported as susceptibility markers to IDDM in Caucasians.

Alleles↗

PubMed2000

Genomic organization of the human CD5 gene.

CD5 is a member of the family of receptors which contain extracellular domains homologous to the type I macrophage scavenger receptor cysteine-rich (SRCR) domain. Here, we compare the exon/intron organization of the human CD5 gene with its mouse homologue, as well as with the human CD6 gene, the closest related member of the SRCR superfamily. The human CD5 gene spans about 24.5 kb and consists of at least 11 exons. These exons are conserved in size, number, and structure in the mouse CD5 homologue. No evidence for the biallelic polymorphism reported in the mouse could be found among a population of 100 individuals of different ethnic origins. The human CD5 gene maps to the Chromosome (Chr) 11q12.2 region, 82 kb downstream from the human CD6 gene, in a head-to-tail orientation, a situation which recalls that reported at mouse Chr 19. The exon/intron organization of the human CD5 and CD6 genes was very similar, differing in the size of intron 1 and the number of exons coding for their cytoplasmic regions. While several isoforms, resulting from alternative splicing of the cytoplasmic exons, have been reported for CD6, we only found evidence of a cytoplasmic tailless CD5 isoform. The conserved structure of the CD5 and CD6 loci, both in mouse and human genomes, supports the notion that the two genes may have evolved from duplication of a primordial gene. The existence of a gene complex for the SRCR superfamily on human Chr 11q (and mouse Chr 19) still remains to be disclosed.

Alternative Splicing↗

PubMed2000

Identification of a novel HLA-Cw07 variant (Cw0714) in a German Caucasian family.

We report herein the identification of a new HLA-Cw*07 allele in two members of a German Caucasian family. This novel allele, designated as Cw*0714, differs from Cw*07011 and Cw*0706 by two nucleotide changes: one at codon 66 (AAC-->AAG) in the exon 2, leading to an amino acid change from Asn to Lys; and another silent substitution at codon 99 (TAT-->TAC) in the exon 3. The latest substitution (T-->C at the third position of codon 99) was not seen in any of the HLA-Cw*07 alleles reported so far, thus being characteristic to the new HLA-Cw*0714 allele.

Alleles↗

PubMed2000

Genomic characterization of CD84 reveals the existence of five isoforms differing in their cytoplasmic domains.

CD84, a new member of the immunoglobulin superfamily, shows high homology with several molecules belonging to the CD2 family of differentiation antigens. By screening a peripheral blood leukocyte cDNA library four CD84 isoforms were obtained differing in their 3' sequence. A reverse transcription-polymerase chain reaction (RT-PCR) analysis confirmed that these isoforms were normally found on leukocytes and a new isoform was identified. To establish the nature of the five isoforms obtained (CD84a, CD84b, CD84c, CD84d and CD84e) the genomic structure of the CD84 gene was determined. Our results show that it is composed of at least eight exons, with an exon coding for the 5' UTR and the leader peptide, two exons coding for each of the two immunoglobulin-like domains, an exon encoding the transmembrane portion and four exons coding for the cytoplasmic domains. The isoforms are generated by several mechanisms: alternative use of exons, reading frame shift, use of a cryptic splice site or absence of splicing. The differential expression of several potentially phosphorylatable residues on the different isoforms could be a way to regulate its possible activity in signal transduction.

Amino Acid Sequence↗

PubMed2000

Assessment of mycophenolic acid-induced immunosuppression: a new approach.

BACKGROUND: Mycophenolic acid (MPA), a metabolite of mycophenolate mofetil (MMF), is an immunosuppressive agent that inhibits inosine monophosphate dehydrogenase (IMPDH), a key enzyme in the ex novo synthesis of GTP. We measured IMPDH activity in peripheral blood mononuclear cells (PBMCs) from MMF-treated patients to evaluate the efficacy of MMF in individual patients. METHODS: IMPDH activity was measured by (3)H released from [2,8-(3)H]IMP that had been formed in the cells from added [2,8-(3)H]hypoxanthine in PBMCs of 35 renal transplant recipients treated with cyclosporin A and corticoids plus MMF: 2 g (n = 10), 1.5 g (n = 7), 1 g (n = 10), or 0 g (n = 8) per day. An alternative method, based on the capacity of the patients' sera to inhibit spontaneous proliferation of the CEM cell line, was also analyzed. RESULTS: The IMPDH activity of PBMCs in transplanted patients was highly variable. For the method based on CEM cell line proliferation: (a) cell proliferation was inhibited only in MMF-treated patients; (b) there was a clear postdose increase in inhibition; (c) inhibition was not affected by other immunosuppressants in vitro or in vivo; (d) inhibition from predose to predose sample was correlated; and (e) when the MMF dosage was <20 mg. kg(-1). day(-1), two groups of patients were identified, one that maintained a high inhibitory capacity in all dose intervals, and one with periods of low inhibitory capacity. CONCLUSIONS: Measurement of the inhibition of CEM cell line proliferation by sera from MMF-treated patients may be useful for evaluating the relative efficacy of MMF treatment in individual patients, especially those receiving low doses of MMF.

Adult↗

PubMed1999

Fibronectin upregulates gelatinase B (MMP-9) and induces coordinated expression of gelatinase A (MMP-2) and its activator MT1-MMP (MMP-14) by human T lymphocyte cell lines. A process repressed through RAS/MAP kinase signaling pathways.

T-lymphocyte migration into tissues requires focal degradation of the basement membrane. In this study, we show that transient adherence to fibronectin induces the production of activated forms of matrix metalloproteinase-2 (MMP-2) and MMP-9, as well as downregulation of tissue inhibitor of metalloproteinase-2 (TIMP-2) by T-cell lines. MMP-2 activation was likely achieved by inducing a coordinated expression of membrane-type matrix metalloproteinase-1 (MMP-14), a major activator of MMP-2. Blocking monoclonal antibodies against alpha4, alpha5, and alphav integrins strongly reduced MMP-2 and MMP-9 production induced by fibronectin. Disrupting actin cytoskeleton organization by cytochalasin D strongly enhanced fibronectin-induced MMP-2 and MMP-9 expression. Inhibiting Src tyrosine kinases with herbimycin A reduced MMP-2 and MMP-9 production with no effect on cell attachment. By contrast, G-protein inhibition by pertussis toxin, or transfection with a dominant negative mutant of Ha-Ras strongly increased fibronectin-induced MMP-2 and MMP-9. Inhibition of PI3 kinase, MAPkinase (MEK1), or p38 MAPkinase by wortmannin, PD 98059, or SB 202190, respectively, strongly promoted fibronectin-induced MMP2 and MMP-9. Cells at high density lost their ability to synthesize MMP-2 and MMP-9 in response to fibronectin and MMP expression was restored by transfection with a dominant-negative mutant of Ha-Ras or by treatment with wortmannin, PD 98059, or SB 202190. Our findings suggest that adhesion to fibronectin transduces both stimulatory (through Src-type tyrosin kinases) and inhibitory signals (through Ras/MAPKinase signaling pathways) for MMP-2 and MMP-9 expression by T lymphocytes and that their relative predominance is regulated by additional stimuli related to cell adhesion, motility, and growth.

Androstadienes↗