Impact des agonistes des TLR sur les réponses B dépendantes des lymphocytes T

Les vaccins protéiques favorisent une immunité à long terme grâce à la différenciation de cellules B mémoires spécifiques de l'antigène et des plasmocytes à longue durée de vie. Pour être efficace, les vaccins doivent induire la différenciation de lymphocytes T auxilaires spécifiques de l'antigène qui sont nécessaires au contrôle des lymphocytes B activés. Il est maintenant clair que cette aide implique une lignée distincte de cellules T auxiliaires nommées lymphocytes T CD4+ folliculaires (Tfh). Puisque la combinaison d'adjuvants semble améliorer de façon synergique la réponse immunitaire, nous avons testé si l'addition d'agonistes des récepteurs Toll (TLR) à d'autres adjuvants vaccinaux contribue aux réponses humorales spécifiques de l'antigène dépendantes des T in vivo. Nous avons constaté que l'addition d'agonistes des TLR dépendants de MyD88 comme le CpG, agoniste de TLR9 utilisé en clinique, ou le LPS, agoniste du TLR4, augmente la différenciation des cellules Tfh spécifiques de l'antigène sans modifier la réponse globale des lymphocytes T spécifiques de l'antigène. Ce phénomène est observé quel que soit l'adjuvant complémenté par un agoniste de TLR: l'adjuvant de Freund incomplet, l'alum ou un adjuvant à base de squalène. En revanche, aucun des agonistes de TLR dépendants de TRIF ont un rôle promoteur sur la différenciation Tfh. L'effet sur les Tfh observé après addition de CpG ou de LPS corrèle avec une augmentation de la réaction du centre germinatif, des plasmocytes spécifiques de l'antigène et des anticorps circulants. Nous avons également démontré que cet effet activateur, en réponse à la signalisation des TLR via MyD88, est orchestré in vivo par la présentation antigénique et l'IL-6 sécrétée par les cellules dendritiques dérivées de monocytes. En revanche, ni les cellules B ni les cellules dendritiques plasmacytoïdes qui sécrètent également de l'IL-6 en réponse aux agonistes de TLR4 et TLR9, sont impliqués dans ce phénomène. Ainsi, alors que les cellules dendritiques conventionnelles initient les réponses des lymphocytes T CD4+ dans les ganglions lymphatiques drainants, le ciblage des cellules dendritiques dérivées de monocytes peut promouvoir le programme Tfh nécessaire au contrôle des cellules B de haute affinité B in vivo.Protein vaccines can promote long-term immunity through the differentiation of Ag-specific high-affinity memory B cells and long-lived plasma cells. To be effective, vaccine priming must induce Ag-specific helper T cells that are required to regulate the emerging B cell response. It is now clear that this cognate T cell help involves a distinct lineage of CD4+ T cells named T Follicular Helper cells (Tfh). Because adjuvant combinations could result in synergistic enhancement of the immune response, we tested whether addition of Toll-like Receptor (TLR) agonists to other vaccine adjuvant contributes to antigen-specific T cell-dependent B cell responses in vivo. We found that MyD88-dependent such as CpG, the TLR9 agonist used in clinics, or LPS, the TLR4 agonist, increased the differentiation of antigen-specific Tfh cells without changing the overall magnitude of the T cell response. This phenomenon was observed irrespective of the adjuvant used: Incomplete Freund's Adjuvant, Alum or squalene-based adjuvant. In contrast, no TRIF-dependent TLR agonists were able to promote Tfh differentiation. The enhancing effect after CpG or LPS addition correlated with an enhancement of germinal center reaction, antigen-specific plasma cells and circulating antibodies. We comprehensively demonstrated that this promoting effect in response to MyD88-dependent TLR signaling was orchestrated in vivo by antigen presentation and IL-6 secreted by monocyte-derived dendritic cells. In contrast, neither B cells nor plasmacytoid dendritic cells that also secreted IL-6 in response to TLR4 and TLR9 agonist were involved in this phenomenon. Thus, while conventional dendritic cells prime and initiate CD4+ T cell responses in the draining lymph nodes, we show that targeting monocyte-derived dendritic cells can specifically enhance the Tfh program needed to regulate high-affinity B cell protection in vivo

Individual capacity for repair of DNA damage and potential uses of stem cell lines for clinical applications:a matter of (genomic) integrity

Public and private human stem cell banking institutions are currently hosting hundreds of thousands partially characterized cell populations, including a significant number of human pluripotentstem cell lines. To be considered for use in clinical applications, stem cell preparations must undergo rigorous testing in order to ensure safety for the recipient. With development of the methodologies for in vitro derivation, ex vivo maintenance and expansion of stem cells and targeted differentiation of multipotent and pluripotent stem cells, many novel issues were added to the list of safety concerns of cell and tissue preparations. These issues are related to the potential changes that may occur in the course of in vitro propagation of stem cells and cell-derived products, how these changes may affect the quality of the preparation; and the potential effects on the recipient. Only a limited number of studies about the role of subtle variations of individual capacity for repair of genotoxic damage in maintenance in vitro of human stem cells are currently available. Nevertheless, the assessment of individual repair capacity may play a crucial role in the safety of use of human stem cells, as it constitutes a major factor in the risk of occurrence of genomic alterations that may seriously compromise the quality of the product. This article reviews the available data about the role of individual capacity for DNA damage repair in different human stem cell types and the potential adverse effects that may occur with the use of cell preparations with inferior repair capacity

SPERMATOKINESIGRAPHIC ANALYSIS OF IMMOBILE SPERMATOZOA IN RANA RIDIBUNDA (PALL) EJACULA

No abstract

Ranking and Repulsing Supermartingales for Reachability in Probabilistic Programs

Computing reachability probabilities is a fundamental problem in the analysis of probabilistic programs. This paper aims at a comprehensive and comparative account on various martingale-based methods for over- and under-approximating reachability probabilities. Based on the existing works that stretch across different communities (formal verification, control theory, etc.), we offer a unifying account. In particular, we emphasize the role of order-theoretic fixed points---a classic topic in computer science---in the analysis of probabilistic programs. This leads us to two new martingale-based techniques, too. We give rigorous proofs for their soundness and completeness. We also make an experimental comparison using our implementation of template-based synthesis algorithms for those martingales

Targeting ATM pathway for therapeutic intervention in cancer

The Ataxia Telangiectasia Mutated gene encodes the ATM protein, a key element in the DNA damage response (DDR) signalling pathway responsible for maintaining genomic integrity within the cell. The ATM protein belongs to a family of large protein kinases containing the phosphatidylinositol-3 catalytic domain, including ATM, ATR and PI3K. ATM provides the crucial link between DNA damage, cell cycle progression and cell death by first sensing double stranded DNA breaks and subsequently phosphorylating and activating other downstream proteins functioning in DNA damage repair, cell cycle arrest and apoptotic pathways,. Mammalian cells are constantly challenged by genotoxic agents from a variety of sources and therefore require a robust sensing and repair mechanism to maintain DNA integrity or activate alternative cell fate pathways. This review covers the role of ATM in DDR signalling and describes the interaction of the ATM kinase with other proteins in order to fulfil its various functions. Special emphasis is given to how the growing knowledge of the DDR can help identify drug targets for cancer therapy, thus providing a rationale for exploiting the ATM pathway in anticancer drug development. Moreover, we discuss how a network modelling approach can be used to identify and characterise ATM inhibitors and predict their therapeutic potential

Structural Raman Enhancement in Graphite Nano-Discs

Raman scattering in disc-shaped graphite nanostructures, etched out of bulk HOPG, are investigated using an excitation wavelength of 532 nm at different laser power. The G-band is fitted using two Lorentzian functions, G(L) and G(H). The difference of Raman shift between the two Lorentzian functions increase with laser power as a consequence of selective absorption and heating of the discs. Further, the G-band from the nanostructured HOPG reveal a Raman enhancement (R-E) of similar to 2.2 and similar to 1.5 for the components associated with the discs (G(L)) and the supporting substrate (G(H)), respectively. The quantitative agreement between the experimental results and performed finite difference time domain calculations make possible to conclude that electromagnetic energy penetrates considerably into the discs from the circular periphery probably due to multiple scattering. In addition, the dependence of R-E of the G(L) component on the laser power is attributed to a temperature dependent electron-phonon coupling

Surgical Tactics and Treatment of Anorectal Abscesses in Adult Patients

INTRODUCTION: Patients with anorectal abscesses (ARAs) represent the most common proctological emergency in the anorectal area. Their wide distribution leads to clinical variety in the type and expression of inflammatory changes in the anorectal area.AIM: The aim of this article is to carry out a study of different surgical methods in order to improve the effectiveness of operative treatment in patients with ARA.MATERIALS AND METHODS: A total of 254 operated adult patients with ARA were studied, of whom 194 (76.4%) were males and 60 (23.6%) were females. The following operative methods were used: incision, revision, and drainage in 137 patients (53.9%), incision, revision, primary fistulotomy with cryptectomy and drainage in 48 patients (18.9%), and incision, revision, with ligation fistulotomy and drainage in 69 patients (27.2%). The average age of the operated patients was 49.57±16.12 years.RESULTS: The ARA types were subcutaneous in 63 patients (24.8%), intersphincteric in 62 patients (24.4%), ischiorectal in 88 patients (34.7%), and supralevator in 41 patients (16.1%). Superficial ARA was found in 107 patients (42.1%), and deep ARA was diagnosed in 147 patients (57.9%). CONCLUSION: The definitive operative treatment was applied in patients with incision, revision, and one-time liquidation of the internal opening by primary or ligation fistulotomy, leading to timely healing without disease chronicity. The principles of necrosectomy and sphincter-preserving manipulations near the external anal sphincter in the treatment of different ARA types should always be a must

Analysis Of Data From The Aerobic Microbiological Landscape In Adult Patients Operated For Anorectal Abscesses

INTRODUCTION: Systematic analyses and studies on the microbiological spectrum of anorectal abscesses (ARAs) are currently lacking in modern proctology. Microorganisms from the colonic flora lead to retrograde infection of the anorectal glands with the subsequent appearance of ARA. AIM: The aim of this article is to analyze the frequency, type, and structure of the aerobic microbiological landscape in adult patients operated for ARA.MATERIALS AND METHODS: A detailed analysis of the microbiological agents was performed in 254 operated adult patients, with a total of 274 isolates, which were divided as follows: 188 monocultures, 20 pairs of aerobic microbial associations, and 46 found sterile. Microbiological studies were performed by bacteriological examination of the purulent exudate taken during the operation.RESULTS: A total of 17 types of microbial cultures were identified. The most common were as follows: E. coli (n=160, 58.4%), Proteus spp. (n=15, 5.5%), Klebsiella spp. (n=11, 4%), Staphylococcus spp. (n=12, 4.4%), Enterococcus faecalis (n=8, 2.9%), Enterobacter cloacae complex (n=6, 2.2%). Monocultures were found in 188 patients (74.0%) and mixed infection with microbial associations in 20 patients (7.9%). Of the isolates, Gram (-) predominated, accounting for 201 (73.3%) strains, and Gram (+) constituted 26 (9.5%).CONCLUSION: So far, there have been only isolated reports on this issue in our country, without systematic studies. This determines the relevance and importance of our study on the aerobic microbiological landscape in operated adult patients with ARA. Routine microbiological screening should be an integral part of the diagnosis of ARA and of great help in the treatment