Antibodies against Tumor associated Carbohydrate Antigen

Cette recherche vise à élucider les mécanismes structurels et les caractéristiques de liaison aux glycanes de l'IgM de Mannitou et de son fragment Fab, en se concentrant sur leurs interactions avec les antigènes glucidiques associés aux tumeurs (TACA), tels que le paucimannose. En étudiant le Fab de Mannitou et des constructions tronquées de la grande protéine d'échafaudage AHNAK, cette recherche fournit des informations fondamentales sur les principes moléculaires qui sous-tendent la reconnaissance des glycanes et la spécificité de la liaison dans les interactions entre anticorps.AHNAK, impliquée dans le glioblastome multiforme (GBM) et d'autres cancers, a été utilisée comme modèle pour l'étude des interactions glycanniques. Étant donné qu'il est difficile d'exprimer la protéine AHNAK complète de 5280 acides aminés, des constructions recombinantes tronquées de son domaine central ont été utilisées pour étudier ses propriétés structurelles, ses schémas de glycosylation et sa liaison avec le Fab de Mannitou. Ces constructions présentaient principalement des conformations dépliées ou flexibles ; cependant, un fragment présentait une glycosylation naturelle en paucimannose, conforme à la littérature, ce qui en fait un système modèle précieux pour l'exploration des interactions de liaison avec les glycanes.L'obtention de structures à haute résolution de l'IgM de pleine longueur pose des défis importants en raison de la flexibilité inhérente de ses régions Fab, qui complique la cristallisation et la détermination structurelle. Ces régions peuvent adopter de multiples conformations, ce qui rend difficile l'obtention d'une structure unique et stable. Bien que la cryo-microscopie électronique (cryo-EM) soit devenue un outil structurel puissant, la flexibilité des Fab de l'IgM limite souvent la résolution, ce qui empêche la visualisation précise des interactions de liaison à l'antigène. Se concentrer sur les fragments Fab isolés de l'IgM pour contourner ces problèmes constitue une solution stratégique. Les fragments Fab, plus stables et mieux définis, permettent une analyse à haute résolution, en contournant la complexité de la structure multivalente de l'IgM. Cette approche facilite l'étude détaillée de la dynamique de liaison et des interactions spécifiques aux Fab, apportant une clarté structurelle essentielle à la compréhension de la base moléculaire des interactions anticorps-antigène.La structure cristalline à haute résolution de la Fab de Mannitou en complexe avec l'heptyl α-D-mannopyranoside a révélé une poche de liaison hydrophobe spécialisée, stabilisée par une liaison cis entre Thr101 et Trp102, facilitant la reconnaissance sélective des glycanes. Les études thermodynamiques indiquent que la configuration monovalente du fragment Fab favorise un mode de liaison déterminé par l'enthalpie, tandis que la structure multivalente de l'IgM complète permet d'améliorer l'affinité de la liaison grâce à un mécanisme coopératif déterminé par l'entropie, ce qui permet des interactions à forte avidité avec une gamme d'antigènes glycaniques.Outre les informations cristallographiques, les analyses SAXS, le dichroïsme circulaire par rayonnement synchrotron (SRCD) et la spectrométrie de masse ont permis de caractériser la glycosylation et la stabilité structurelle du Fab de Mannitou. La glycosylation à l'Asn164 a stabilisé la forme monomérique, réduisant les interactions non spécifiques et empêchant l'agrégation. Des oligomères d'ordre supérieur, en particulier des espèces dimériques, ont été observés en solution, ce qui suggère un potentiel de multimérisation. Alors que le SAXS et la SRCD ont fourni des informations structurelles à basse résolution sur ces formes, la structure à haute résolution de l'état dimérique reste insaisissable en raison d'un manque de modèles appropriés.This research aims to elucidate the structural mechanisms and glycan-binding characteristics of Mannitou IgM and its Fab fragment, focusing on their interactions with tumour-associated carbohydrate antigens (TACAs), such as paucimannose. By studying Mannitou Fab and truncated constructs of the large scaffolding protein AHNAK, this research provides foundational insights into the molecular principles underlying glycan recognition and binding specificity in antibody interactions.AHNAK, involved in glioblastoma multiforme (GBM) and other cancers, was employed as a model for studying glycan interactions. Given the challenge of expressing the full-length 5280-amino acid AHNAK protein, truncated recombinant constructs of its central domain were utilised to investigate its structural properties, glycosylation patterns, and binding with Mannitou Fab. These constructs predominantly exhibited unfolded or flexible conformations; however, one fragment displayed natural paucimannose glycosylation, consistent with the literature, making it a valuable model system for exploring glycan-binding interactions.Obtaining high-resolution structures of full-length IgM poses significant challenges due to the inherent flexibility of its Fab regions, which complicates crystallisation and structural determination. These regions can adopt multiple conformations, making capturing a single, stable structure difficult. Although cryo-electron microscopy (cryo-EM) has advanced as a powerful structural tool, the Fab flexibility in IgM frequently limits resolution, hindering precise visualisation of antigen-binding interactions. Focusing on isolated Fab fragments of IgM to circumvent these issues provides a strategic solution. The Fab fragments, being more stable and defined, allow for high-resolution analysis, bypassing the complexity of IgM's multivalent structure. This approach facilitates the detailed study of Fab-specific binding dynamics and interactions, providing structural clarity essential for understanding the molecular basis of antibody-antigen interactions.The high-resolution crystal structure of Mannitou Fab in complex with heptyl α-D-mannopyranoside revealed a specialised hydrophobic binding pocket stabilised by a non-proline cis-peptide bond between Thr101 and Trp102, facilitating selective glycan recognition. Thermodynamic studies indicate that the Fab fragment's monovalent configuration favours an enthalpy-driven binding mode, while the multivalent structure of full IgM allows for enhanced binding affinity through an entropy-driven, cooperative mechanism, enabling high-avidity interactions with a range of glycan antigens.In addition to crystallographic insights, SAXS, synchrotron radiation circular dichroism (SRCD), and mass spectrometry analyses characterised the glycosylation and structural stability of Mannitou Fab. Glycosylation at Asn164 stabilised the monomeric form, reducing nonspecific interactions and preventing aggregation. Higher-order oligomers, particularly dimeric species, were observed in solution, suggesting potential for multimerisation. While SAXS and SRCD provided low-resolution structural insights into these forms, the high-resolution structure of the dimeric state remains elusive due to a lack of proper models.Collectively, this research highlights the significance of Fab-specific studies in resolving the structural complexities of antibody-antigen binding at high resolution. It contributes to a deeper understanding of the biophysical principles underlying antibody specificity and affinity for carbohydrate antigens

Natural antibodies : protecting role of IgM in glioblastoma and brain tumours

Background: Glioblastoma is a grade IV astrocytoma with an average survival span for patients of 18 months after initial diagnosis and no standard treatment protocol is available. Therefore, there is a need to search for novel approaches to target glioblastoma. Objectives: This review intends to capture the role of immunoglobulin-M in cancer, more specifically in glioblastoma multiforme (GBM), and to compile the latest developments and immunological pathways relevant to glioblastoma. Methods: Information on glioblastoma, cancer microenvironment, cancer therapeutics, and how to improve the scenario were obtained from scientific literature databases such as Pubmed, Medline, Google Scholar, Science Direct, Springer, Wiley online library, and some data was harvested from regulatory and compliance databases such as clinicaltrials.gov, FDA database, and WHO Globocan. Results and Conclusion: Currently, only a limited number of therapies are approved for GBM, and no standard care is in place in case of disease relapse, necessitating a possible broader perspective in looking at the disease and its underlying mechanisms

Natural Antibodies: Protecting Role of IgM in Glioblastoma and Brain Tumours

Background: Glioblastoma is a grade IV astrocytoma with an average survival span for patients of 18 months after initial diagnosis and no standard treatment protocol is available. Therefore, there is a need to search for novel approaches to target glioblastoma. Objectives: This review intends to capture the role of immunoglobulin-M in cancer, more specifically in glioblastoma multiforme (GBM), and to compile the latest developments and immunological pathways relevant to glioblastoma. Methods: Information on glioblastoma, cancer microenvironment, cancer therapeutics, and how to improve the scenario were obtained from scientific literature databases such as Pubmed, Medline, Google Scholar, Science Direct, Springer, Wiley online library, and some data was harvested from regulatory and compliance databases such as clinicaltrials.gov, FDA database, and WHO Globocan. Results and Conclusions: Currently, only a limited number of therapies are approved for GBM, and no standard care is in place in case of disease relapse, necessitating a possible broader perspective in looking at the disease and its underlying mechanisms. </jats:sec

Estimating and comparing the trends of fertility pattern from various birth cohorts in rural hilly population of Uttarakhand

Background: Nuptiality and fertility are often studied together because nuptiality affects fertility. If childbearing tends to be confined to married couples, as it is in many societies, higher proportion of women marrying will tend to higher fertility and vice versa. Population change may, therefore, be indirectly influenced by nuptiality.Objective: The objective of this study was to estimate and compare the fertility status of women with age group of 17–86 years among seven different cohorts.Materials and Methods: A community-based cross-sectional study conducted through predesigned questionnaire in the Dehradun district of Uttarakhand. The subjects of the study were the local residents of selected hilly rural areas of Dehradun. Women, who were ever married and unmarried, born in between 1931 and 2000. The study has been approved by the ethics committee of the university. Informed consent in the local language has been taken from subjects during filling predesigned questionnaire.Results: The results of the study show trend in the home delivery have been observed to be declining with the respective birth cohorts. The trend in the data for the respective factors gravida and parity is observed to be decreasing at consecutive cohorts. The results also show differentials between gravida and parity according to religion. It shows that religion shows statistically significant between gravida and parity. The cohort 1931-1940 and 1971-1980 shows highly significant according to religion in gravida. In parity, cohort 1961-1970 and 1981-1990 also shows highly significant value according to religion.Conclusion: The maternal health policies in developing countries such as India should be viewed as central goals together with achievement of MDG-5 targets. The enormous imbalances in maternity care underline the requirement for successful arrangement of administrations

Bridging the attitude-behavior gap in sustainable consumption for electric vehicles in India.: A theoretical proposition

The paper re-evaluates the attitude-behavior gap towards sustainable consumption, by looking at the cognitive aspects of consumer purchase behavior. The study explores the gap between purchase attitude formation and sustainable consumption behavior using hedonistic and aesthetic constructs for electric vehicles marketing strategy as an example. The study focuses on OLA Electric Two-wheeler (OLA S1) as an example of marketing a green product concerning electric vehicles in India. The study concludes that OLA Electric's marketing strategy focuses on environmental concerns, demographic variables, and hedonistic behavior to transform the future of mobility with its electric scooters by 2025 in India. OLA Electric markets itself with a full complement of consumer benefits compared to other economical electric two-wheeler vehicles, although sustainability is one of the important aspects of OLA’s two-wheeler, the primary focus of OLA’s electric marketing communication strategy is based on hedonistic and aesthetic factors. The study concludes that pricing strategies, awareness and the absence of hedonistic and aesthetics factors are the main reasons for the Attitude -Behavior Gap. Keywords: Attitude-behavior gap, Sustainability, Ola electric vehicles (OLA S1), Hedonic, Sustainable consumptio

Native glycosylation and binding of the antidepressant paroxetine in a low-resolution crystal structure of human myeloperoxidase.

Human myeloperoxidase (MPO) utilizes hydrogen peroxide to oxidize organic compounds and as such plays an essential role in cell-component synthesis, in metabolic and elimination pathways, and in the front-line defence against pathogens. Moreover, MPO is increasingly being reported to play a role in inflammation. The enzymatic activity of MPO has also been shown to depend on its glycosylation. Mammalian MPO crystal structures deposited in the Protein Data Bank (PDB) present only a partial identification of their glycosylation. Here, a newly obtained crystal structure of MPO containing four disulfide-linked dimers and showing an elaborate collection of glycans is reported. These are compared with the glycans identified in proteomics studies and from 18 human MPO structures available in the PDB. The crystal structure also contains bound paroxetine, a blocker of serotonin reuptake that has previously been identified as an irreversible inhibitor of MPO, in the presence of thiocyanate, a physiological substrate of MPO.info:eu-repo/semantics/publishe