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19 result(s) for "Apoil, Pol-André"
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Influence of the MHC genotype on the progression of experimental SIV infection in the Mauritian cynomolgus macaque
Experimental infection of Mauritian cynomolgus macaques by simian immunodeficiency virus is a representative model of HIV infection, currently in favour for evaluating the efficacy of new preventive or curative treatments. Extensive studies of major histocompatibility complex (MHC) polymorphism by microsatellites revealed seven haplotypes (H1–H7). We present statistical evidence of the influence of MHC polymorphism on the set-point plasma viral load (PVL). Our analysis was based on the study of 45 Mauritian cynomolgus macaques inoculated by intravenous or intrarectal injection of a 50 AID50 dose of the SIVmac251 virus. The animals received no treatment before or after the inoculation. MHC polymorphism was investigated by means of 20 microsatellites distributed across the MHC and by DRB genotyping using the DGGE sequencing method. Statistical analysis with Unphased software revealed that two markers located in the class IB region significantly influenced the Log PVL and that three class IB haplotypes were significantly associated with lower (H2 or H6) or higher (H4) set-point Log PVL values. Although the impact of MHC on Log PVL was found to be low (around one Log10), it is important to dispose of animals paired for their MHC genotypes, each animal tested for a given treatment and its untreated control, to minimize the influence of the MHC and clearly reveal the effect of the treatment.
Distinct effect of age, sex, and CMV seropositivity on dendritic cells and monocytes in human blood
We analyzed the impact of age, sex, and CMV on blood monocyte and dendritic cell (DC) subpopulations in 256 healthy individuals aged from 19 to 96 years. Flow cytometry was performed on whole blood within the 4 h following blood drawing. Myeloid (mDC) and plasmacytoid DC (pDC), classical, intermediate, and nonclassical monocytes were enumerated by means of TruCount tubes (BD Biosciences). We provided reference values for mDC, pDC and the three monocyte subpopulations. The numbers of classical, intermediate, and nonclassical monocytes slightly increased with age while the numbers of mDC and pDC did not vary significantly. The level of expression of CD64 and CD163 on monocytes significantly increased with age while HLA‐DR expression did not vary significantly. More precisely, CD163 expression level on intermediate monocyte slightly increased with age in women only (Spearman P = 0.019) while CD64 expression increased on monocytes in CMV‐positive individuals only. We observed that sex had almost no impact on the numbers of monocytes and DC and on their expression level of CD64 and HLA‐DR. We observed a significant decrease in the numbers of pDC with age in CMV‐positive individuals, but not in CMV negative individuals. This suggests that the lifelong subclinical infection by CMV could influence the number of circulating DC of lymphoid origin. In contrast, CMV serostatus had no significant impact on absolute numbers of mDC and monocytes. We analyzed the impact of age, sex, and CMV on blood monocyte and dendritic cell (DC) subpopulations in 256 healthy individuals aged from 19 to 96 years. We observed an age‐related slight increase in classical, intermediate, and nonclassical monocytes, and a moderate but significant decrease in pDC in CMV‐positive individuals only. The numbers of mDC did not vary significantly with age. The level of expression of CD64 and CD163 on monocytes significantly increased with age, while HLA‐DR expression did not vary significantly.
Study of cynomolgus monkey (Macaca fascicularis) Mhc DRB gene polymorphism in four populations
The cynomolgus macaque ( Macaca fascicularis ) is currently used as an animal model in various fields of immunology especially in the development of innovative vaccines for the prevention and treatment of infectious diseases. The polymorphism of the major histocompatibility complex (MHC) influences the development of adaptive immune responses, and it is crucial to characterize the polymorphism of cynomolgus MHC genes. Among all macaque species, the cynomolgus macaque has the most diversified geographical area encompassing continental and insular populations. By the study of a large sample of animals from the Philippines ( N  = 359), we have characterized 20 DRB haplotypes. The DRB genotyping was performed by denaturing gradient gel electrophoresis (DGGE) sequencing of exon 2 and was confirmed by polymerase chain reaction–sequence-specific oligonucleotide. The DRB and DRA cDNA of 126 animals were characterized by cloning and sequencing. By means of DGGE sequencing, we characterized the polymorphism of genomic DRB exon 2 in three other cynomolgus macaque population samples (Java, Vietnam, and Mauritius), and we discuss about the origin of the founders of the Mauritian and the Filipino cynomolgus macaque populations.
Characterization of MHC class I transcripts of a Malaysian cynomolgus macaque by high-throughput pyrosequencing and EST libraries
We characterized the repertoire of MHC class I transcripts of a Malaysian cynomolgus macaque by the study of EST libraries derived from the mRNA extracted from six tissues (thymus, spleen, bone marrow, liver, heart and pancreas). The MHC class I transcripts present in a lymph node of the same animal were characterized by pyrosequencing of amplified cDNA fragments (515 bp from exon 2 to the beginning of exon 4). All pyrosequence consensus sequences, but three corresponding to rare transcripts, were identical to those obtained from EST libraries. In total, we characterized 19 classical class I transcripts in the Malaysian macaque studied here. By means of high-throughput sequencing of exon 2 amplified from the genomic DNA (190 bp), we characterized 38 classical class I genes in the genome of this animal. By comparison, using the same method, we found 23 classical class I genes in the genome of a MHC homozygous Mauritian animal (H2/H2). All these results suggested that the Malaysian animal was most probably heterozygous. This study reveals that the high-throughput pyrosequencing allows not only to characterize the MHC class I transcripts but also to estimate the number of MHC class I genes in the genome of cynomolgus macaque.
Human Fibroblasts Share Immunosuppressive Properties with Bone Marrow Mesenchymal Stem Cells
Introduction Bone marrow mesenchymal stem cells (BM-MSCs) and adipose tissue-derived stem cells share immunosuppressive capacities, suggesting that the latter could be a general property of stromal cells. Methods To check this hypothesis, we compared human BM-MSC and fibroblasts for their in vitro multi-potentiality, expandability and their immunomodulatory properties under normalized optimized culture conditions. Results We report that, unlike BM-MSCs, fibroblasts cannot differentiate in vitro into adipocytes and osteoblasts and differ from BM-MSCs by the expression of membrane CD106, CD10 and CD26 and by the expression of collagen VII mRNA. Like BM-MSCs, fibroblasts are unable to provoke in vitro allogeneic reactions, but strongly suppress lymphocyte proliferation induced by allogeneic mixed lymphocyte culture (MLC) or mitogens. We show that fibroblasts' immunosuppressive capacity is independent from prostaglandin E2, IL-10 and the tryptophan catabolising enzyme indoleamine 2,3-dioxygenase and is not abrogated after the depletion of CD8+ T lymphocytes, NK cells and monocytes. Conclusion Finally, fibroblasts and BM-MSCs act at an early stage through blockage of lymphocyte activation, as demonstrated by down-regulation of GZMB (granzyme B) and IL2RA (CD25) expression.
Study of cynomolgus monkey (Macaca fascicularis) DRA polymorphism in four populations
To describe the polymorphism of the DRA gene in Macaca fascicularis, we have studied 141 animals either at cDNA level (78 animals from Mauritius, the Philippines, and Vietnam) or genomic level (63 animals from the Philippines, Indonesia, and Vietnam). In total, we characterized 22 cDNA DRA alleles, 13 of which had not been described until now. In the Mauritius population, we confirmed the presence of three DRA alleles. In the Philippine and Vietnam populations, we observed 11 and 14 DRA alleles, respectively. Only two alleles were present in all three populations. All DRA alleles but one differ from the consensus sequence by one to three mutations, most being synonymous; so, only seven DR alpha proteins were deduced from the 22 cDNA alleles. One DRA cDNA allele, Mafa-DRA*02010101, differs from all other alleles by 11 to 14 mutations of which only four are non-synonymous. The two amino acid changes inside the peptide groove of Mafa-DRA*02010101 are highly conservative. The very low proportion of non-synonymous/synonymous mutations is compatible with a purifying selection which is comparable to all previous observations concerning the evolution of the DRA gene in mammals. Homologues of the allele Mafa-DRA*02010101 are also found in two other Asian macaques (Macaca mulatta and Macaca nemestrina). The forces able to maintain this highly divergent allele in three different macaque species remain hypothetical.
Study of Cynomolgus monkey (Macaca fascicularis) MhcDRB (Mafa-DRB) polymorphism in two populations
Cynomolgus monkey is one of the macaque species currently used as an animal model for experimental surgery and medicine, in particular, to experiment new drugs or therapy protocols designed for the prevention of allograft rejection. In this field, it is of utmost importance to select histoincompatible recipient-donor pairs. One way to ensure incompatibility between donor and recipient is to check their major histocompatibility complex (MHC) genotypes at the loci playing a determinant role in histocompatibility. We report in this paper on the cynomolgus monkey DRB polymorphism evidenced by sequencing of amplified exon 2 separated either by denaturing gradient gel electrophoresis (DGGE), or by cloning. By the study of 253 unrelated animals from two populations (Mauritius and The Philippines), we characterized 50 exon 2 sequences among which 28 were identical to sequences already reported in Macaca fascicularis or other macaque species (Macaca mulatta, Macaca nemestrina). By cloning and sequencing DRB cDNA, we revealed two additional DRB alleles. Out of the 20 haplotypes that we defined here, only two were found in both populations. The functional impact of DR incompatibility was studied in vitro by mixed lymphocyte culture.
Peeling Skin Syndrome Type 1: Dupilumab Reduces IgE, But Not Skin Anomalies
Peeling skin syndrome type 1 (PSS1) (OMIM #270,300) is a very rare autosomal-recessive genetic disease due to loss-of-function mutations in CDSN which encodes corneodesmosin [1], an adhesive protein specific to corneodesmosomes, the adhesive junctions of the stratum corneum. Patients present with continuous superficial peeling and inflammatory skin. Associated findings include severe refractory pruritus, skin infections, growth delay in infancy, and atopic manifestations (food allergy, urticaria, asthma). Quality of life (QOL) is often impaired and there is no effective therapy. Emollients are commonly used but are of limited efficacy.
Impact of MHC class II polymorphism on blood counts of CD4+ T lymphocytes in macaque
While the number of peripheral blood T lymphocytes and of their two main subsets (CD4+CD8− and CD4−CD8+) varies little in a given healthy individual, substantial variation is observed between individuals. It was proposed that these counts could be influenced by MHC polymorphisms because of the well-established role of MHC molecules in thymic T lymphocyte maturation and presentation of antigenic peptides to peripheral T lymphocytes. To test this hypothesis, we have chosen the crab-eating macaque (Macaca fascicularis), an animal model phylogenetically close to man. We selected the Philippine macaque population because of a restriction of the MHC polymorphism in this islander population. Peripheral blood lymphocytes were counted with an automated analyzer and T lymphocyte subsets were assessed by immunolabeling and flow cytometry. The MHC polymorphism was investigated in 200 unrelated subjects using 14 microsatellites markers distributed across the MHC and the DRB locus that was genotyped by denaturing gradient gel electrophoresis and sequencing. All markers were in Hardy-Weinberg equilibrium. Allelic associations were tested with the UNPHASED software. We revealed a significant influence of the MHC class II region on CD4+ T lymphocyte blood count with the largest effect associated with a two-locus haplotypes combining the DRACA allele 274 and the DRB haplotype #8a (p < 8 × 10⁻⁷). Our data should stimulate a similar association study of the CD4+ T cell counts in humans.