Estudio en aves silvestres de canto ("Passeriformes") de las moléculas MHC y reclasificación molecular de la familia "Carduelini"

The Major Histocompatibility Complex (MHC) comprises the most polymorphic loci in animals. MHC plays an important role during the first steps of the immune response in vertebrates. In humans, MHC molecules (also named human leukocyte antigens, HLA) were initially regarded as class I or class II molecules. Each of them, presents to different T cells subsets. MHC class I molecules, are heterodimers in which the heavy chain (alpha) has three extracellular domains, two of which (alpha 1 and alpha 2) are polymorphic and conform the antigen recognition sites (ARS). The ARS is thought to be subjected to balancing selection for variability, which is the cause of the very high polymorphism of the MHC molecules. Different pathogenic epitopes would be the evolutionary force causing balancing selection. MHC class I genes have been completely sequenced (α1 and α2 protein domains) and thoroughly studied in Gallus gallus (chicken) as well as in mammals. In fact, the MHC locus was first defined in chicken, specifically in the highly consanguineous variety „Leghorn‟. It has been found that, in the case of chickens the MHC genetic region is considerably smaller than it is in mammals (remarkably shorter introns were found in chickens), and is organized quite differently. The noteworthy presence of short introns in chickens; supported the hypothesis that chicken‟s MHC represented a „minimal essential MHC‟. Until now, it has been assumed that chicken (order Galliformes) MHC was similar to all species included in the whole class Aves...

A deimmunised form of the ribotoxin, α-sarcin, lacking CD4+ T cell epitopes and its use as an immunotoxin warhead

Fungal ribotoxins that block protein synthesis can be useful warheads in the context of a targeted immunotoxin. α-Sarcin is a small (17 kDa) fungal ribonuclease produced by Aspergillus giganteus that functions by catalytically cleaving a single phosphodiester bond in the sarcin–ricin loop of the large ribosomal subunit, thus making the ribosome unrecognisable to elongation factors and leading to inhibition of protein synthesis. Peptide mapping using an ex vivo human T cell assay determined that α-sarcin contained two T cell epitopes; one in the N-terminal 20 amino acids and the other in the C-terminal 20 amino acids. Various mutations were tested individually within each epitope and then in combination to isolate deimmunised α-sarcin variants that had the desired properties of silencing T cell epitopes and retention of the ability to inhibit protein synthesis (equivalent to wild-type, WT α-sarcin). A deimmunised variant (D9T/Q142T) demonstrated a complete lack of T cell activation in in vitro whole protein human T cell assays using peripheral blood mononuclear cells from donors with diverse HLA allotypes. Generation of an immunotoxin by fusion of the D9T/Q142T variant to a single-chain Fv targeting Her2 demonstrated potent cell killing equivalent to a fusion protein comprising the WT α-sarcin. These results represent the first fungal ribotoxin to be deimmunised with the potential to construct a new generation of deimmunised immunotoxin therapeutics.

Études du ciblage intracellulaire des molécules non classiques du complexe majeur d'histocompatibilité de classe II

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.

Ubiquitination et ciblage des molécules du complexe majeur d'histocompatibilité de classe-II aux exosomes

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Outcomes after Unrelated Umbilical Cord Blood Transplantation for Children with Osteopetrosis.

Hematopoietic stem cell transplantation (HSCT) is the only curative treatment for most children with osteopetrosis (OP). Timing of HSCT is critical; therefore, umbilical cord blood transplantation (UCBT) is an attractive option. We analyzed outcomes after UCBT in 51 OP children. Median age at UCBT was 6 months. Seventy-seven percent of the cord blood grafts had 0 or 1 HLA disparity with the recipient. Conditioning regimen was myeloablative (mostly busulfan-based in 84% and treosulfan-based in 10%). Antithymocyte globulin was given to 90% of patients. Median number of total nucleated and CD34(+) cells infused was 14 × 10(7)/kg and 3.4 × 10(5)/kg, respectively. Median follow-up for survivors was 74 months. Cumulative incidence (CI) of neutrophil recovery was 67% with a median time to recovery of 23 days; 33% of patients had graft failure, 81% of engrafted patients had full donor engraftment, and 19% had mixed donor chimerism. Day 100 CI of acute graft-versus-host disease (grades II to IV) was 31% and 6-year CI of chronic graft-versus-host disease was 21%. Mechanical ventilation was required in 28%, and veno-occlusive disease was diagnosed in 16% of cases. Six-year overall survival rate was 46%. Comparative studies with other alternative donors should be performed to evaluate whether UCBT remains a valid alternative for children with OP without an HLA-matched donor.

Études du ciblage intracellulaire des molécules non classiques du complexe majeur d'histocompatibilité de classe II

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.

Ubiquitination et ciblage des molécules du complexe majeur d'histocompatibilité de classe-II aux exosomes

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Immunologically silent cancer clone transmission from mother to offspring

Rare cases of possible materno-fetal transmission of cancer have been recorded over the past 100 years but evidence for a shared cancer clone has been very limited. We provide genetic evidence for mother to offspring transmission, in utero, of a leukemic cell clone. Maternal and infant cancer clones shared the same unique BCR-ABL1 genomic fusion sequence, indicating a shared, single-cell origin. Microsatellite markers in the infant cancer were all of maternal origin. Additionally, the infant, maternally- derived cancer cells had a major deletion on one copy of chromosome 6p that included deletion of HLA alleles that were not inherited by the infant (i.e., foreign to the infant), suggesting a possible mechanism for immune evasion.

Proprioception in ankle sprain from exercises and bandages

Ankle sprains are the most common injuries in sports, usually causing damage to the lateral ligaments. Recurrence has as usual result permanent instability, and thus loss of proprioception. This fact, together with residual symptoms, is what is known as chronic ankle instability, CAI, or FAI, if it is functional. This problem tries to be solved by improving musculoskeletal stability and proprioception by the application of bandages and performing exercises. The aim of this study has been to review articles (meta-analisis, systematic reviews and revisions) published in 2009-2015 in PubMed, Medline, ENFISPO and BUCea, using keywords such as “sprain instability”, “sprain proprioception”, “chronic ankle instability”. Evidence affirms that there does exist decreased proprioception in patients who suffer from CAI. Rehabilitation exercise regimen is indicated as a treatment because it generates a subjective improvement reported by the patient, and the application of bandages works like a sprain prevention method limiting the range of motion, reducing joint instability and increasing confidence during exercise. As podiatrists we should recommend proprioception exercises to all athletes in a preventive way, and those with CAI or FAI, as a rehabilitation programme, together with the application of bandages. However, further studies should be generated focusing on ways of improving proprioception, and on the exercise patterns that provide the maximum benefit.

Étude du profil des populations cellulaires du sang en vue d’une application au diagnostic du lupus érythémateux disséminé

Le lupus érythémateux disséminé (LED) est une maladie auto-immune systémique dont le diagnostic est très complexe. Le clinicien doit baser son diagnostic sur une liste de 11 critères reliés à des observations cliniques et à des mesures sérologiques. Afin de faciliter ce diagnostic, plusieurs groupes recherchent de nouveaux marqueurs biologiques quantifiables. C’est dans ce but que la cytométrie en flux a été utilisée afin de comparer les cellules du sang des patients et celles de sujets sains. La caractérisation exhaustive des sous-populations cellulaires montre que l’expression de HLA-DR est amplifiée chez les patients même si la maladie est inactive. De plus, l’analyse du contenu sérique en cytokines inflammatoires a montré que la quantité de GM-CSF était plus importante chez les patients LED. Nos travaux suggèrent que HLA-DR et GM-CSF pourraient être considérés comme des candidats intéressants dans les études sur le diagnostic du LED.

Characterization of cancer/testis antigen MAGE-A11 for immunotherapy of prostate cancer

Les antigènes testiculaires du cancer sont des cibles idéales pour l’immunothérapie du cancer car ce sont des protéines immunogéniques dont l’expression est restreinte aux cellules germinales et au cancer. Le but de cette étude est d’évaluer le potentiel de MAGE-A11, un antigène testiculaire du cancer, comme cible pour développer un vaccin contre le cancer de la prostate. Pour ce faire, l’anticorps monoclonal 5C4 qui a la capacité de reconnaître la présence de MAGE-A11 dans les tissus fixés et inclus en paraffine a été produit. De plus, l’expression de MAGE-A11 a été analysée sur plusieurs lignées de cellules cancéreuses. Il a été démontré que MAGE-A11 est exprimé dans plusieurs types de cancers notamment dans le cancer du côlon et du cerveau. Finalement, nous avons identifié trois épitopes du CMH classe II HLA-DR1 dans la protéine MAGE-A11 confirmant ainsi l’immunogénicité de cet antigène et son potentiel comme cible pour l’immunothérapie du cancer.

NK Cells of Kidney Transplant Recipients Display an Activated Phenotype that Is Influenced by Immunosuppression and Pathological Staging

To explore phenotype and function of NK cells in kidney transplant recipients, we investigated the peripheral NK cell repertoire, capacity to respond to various stimuli and impact of immunosuppressive drugs on NK cell activity in kidney transplant recipients. CD56(dim) NK cells of kidney transplanted patients displayed an activated phenotype characterized by significantly decreased surface expression of CD16 (p=0.0003), CD226 (p<0.0001), CD161 (p=0.0139) and simultaneously increased expression of activation markers like HLA-DR (p=0.0011) and CD25 (p=0.0015). Upon in vitro stimulation via Ca++-dependent signals, down-modulation of CD16 was associated with induction of interferon (IFN)-gamma expression. CD16 modulation and secretion of NFAT-dependent cytokines such as IFN-gamma, TNF-alpha, IL-10 and IL-31 were significantly suppressed by treatment of isolated NK cells with calcineurin inhibitors but not with mTOR inhibitors. In kidney transplant recipients, IFN-gamma production was retained in response to HLA class I-negative target cells and to non-specific stimuli, respectively. However, secretion of other cytokines like IL-13, IL-17, IL-22 and IL-31 was significantly reduced compared to healthy donors. In contrast to suppression of cytokine expression at the transcriptional level, cytotoxin release, i.e. perforin, granzyme A/B, was not affected by immunosuppression in vitro and in vivo in patients as well as in healthy donors. Thus, immunosuppressive treatment affects NK cell function at the level of NFAT-dependent gene expression whereby calcineurin inhibitors primarily impair cytokine secretion while mTOR inhibitors have only marginal effects. Taken together, NK cells may serve as indicators for immunosuppression and may facilitate a personalized adjustment of immunosuppressive medication in kidney transplant recipients.

Doença enxerto-versus hospedeiro: determinação da expressão de genes e alterações de vias associadas ao sistema imunológico usando metodos da biofísica

O transplante de medula óssea (TMO) é um procedimento terapêutico importante em casos relacionados à pacientes com leucemia ou linfoma. Em decorrência desse processo, uma reação conhecida como doença enxerto-versus-hospedeiro (GVHD) pode ocorrer em pacientes susceptíveis como conseqüência da presença de células imunocompetentes do doador. Entretanto, não existe um modelo para descrever completamente as ações relacionadas ao mecanismo imunológico da GVHD desde a fase que inicializa a doença até a fase efetora. O Objetivo geral deste estudo é a investigação da resposta imunológica considerando-se o sistema HLA (antígenos leucocitários humano) em pacientes que desenvolveram a GVHD em decorrência do TMO. O National Cancer Institute (NCI) – Pathway interaction Database e Reactome foram usados como bases de dados com o objetivo de se estudar a expressão de genes e vias relacionados às Classes I e II do sistema HLA (antígenos leucocitários humano). O estudo considerou a mudança de expressão de genes relacionados às 17 vias do sistema imunológico com potencialidade para se expressar em pacientes que desenvolveram a GVHD associada à TMO. Dados referentes aos transcriptomas foram obtidos utilizando-se a plataforma GPL570 Affymetrix Genoma Humano U133 Plus. A atividade relativa foi usada para determinar as alterações das vias em amostras de GVHD em relação ao controle. As análises foram realizadas utilizando-se o software Via Complex e Bioconductor. Observou-se aumento significativo da expressão de genes ralacionados às vias do sistema imune adaptativo, antígenos associados às Classe I e II do HLA, fosforilação de CD3 e CD247, sinalização dos receptores de células T em CD4+ nativas e ativação de NF-kapa β nas células B. Também observou-se alterações significativas na mudança de expressão dos genes associados às vias relacionadas à super família de moléculas B7:CD28\CTLA-4 quando comparadas ao controle. Isso pode indicar a necessidade de geração de um segundo sinal co-estimulador em GVHD, acionado pelas moléculas dessa super família. O aumento da expressão do gene CD69 nas amostras experimentais caracteriza a ativação celular e, portanto, a sinalização de estímulos em GVHD. Os achados obtidos neste estudo contribuem para melhor elucidar o mecanismo imunopatogênico associado à GVHD. P

Células madre mesenquimales orales: estado del arte en Odontología

Desde la organogénesis y hasta estadios adultos, las células madre mesenquimales participan activamente dando origen y manteniéndola homeostasis del organismo. En la cavidad oral han sido aisladas desde variadas estructuras del órgano dental tales como el ligamento periodontal, pulpa dental, tejido gingival, folículo dental y papila apical significando una prometedora fuente de células madre mesenquimales las que pueden ser caracterizadas de acuerdo a los criterios mínimos establecidos por "The International Society for Cellular Therapy" que son: a) La adherencia al plástico; b) La expresión de marcadores CD73, CD90, CD105 y la carencia de CD34, CD45, CD14, CD11, CD79, CD19 y HLA-DR (clase II); c) Capacidad multipotencial de diferenciación hacia linaje osteogénico, condrogénico y adipogénico. El objetivo de esta revisión consiste en realizar un levantamiento de la situación actual de este tema efectuando una revisión comprensiva de la literatura en los campos de; identificación a través demarcadores de superficie, aislamiento por medio de mecanismos de digestión enzimática o explante, almacenamiento atendiendo a la necesidad de suprimir el uso de suero fetal bovino como medio de cultivo en un esfuerzo por avanzar hacia aplicaciones terapéuticas, banca o criopreservación destacando nuevas experiencia en este campo como lo es la criopreservación de piezas dentales completas gracias a la tecnología láser Nd:YAG. Y, finalmente, las aplicaciones clínicas que promete este grupo de células a través de la medicina regenerativa y la ingeniería tisular tanto en el campo de la odontología como la medicina general.

Non-Celiac Gluten Sensitivity and Autoimmunity. A Case Report

Introduction, objective: To present a case report in which the finding of non-coeliac gluten sensitivity was decisive for the treatment of a complex autoimmune disease. Materials and methods: A 43-year-old woman with polyarthritis, psoriatic features, anti-SSA/Ro and anti-cyclic citrullinated peptide antibodies, with refractory course, was evaluated for gluten sensitivity despite negative serology for coeliac disease. Results: The patient carried the HLA DQ2 haplotype and duodenal biopsy showed lymphocytic enteritis. A gluten-free diet resolved the clinical picture and permitted tapering of immunosuppressive therapy. Conclusion: Non-coeliac gluten sensitivity can be associated with autoimmunity despite the absence of the specific autoantibodies of coeliac disease.