Glycosylation of the IgG-Fc is essential for optimal binding and activation of Fcγ receptors and the C1q component of complement. However, it has been reported that the effector functions are ...down-regulated when the Fc glycans terminate in sialic acid residues and that sialylated IgG mediates anti-inflammatory effects of intravenous immunoglobulin (IVIG). Although recombinant IgG is hypo-sialylated, Fc sialylation is shown to be markedly increased when a mouse/human chimeric IgG3 Phe243Ala (F243A) variant is expressed in Chinese hamster ovary (CHO)-K1 cells. Here we investigate whether sialylation is increased in IgG1 F243A when expressed in CHO-K1, mouse myeloma J558L and human embryonic kidney (HEK) 293. Although the sialylation level was 2–5% for IgG1 wild type (WT), it was increased to 31%, 10% and 33% for the variant from CHO-K1, J558L and HEK293 cells, respectively. Interestingly, an increased addition of bisecting GlcNAc and α(1-3)-galactose residues to the Fc glycan was observed for HEK293-derived and J558L-derived IgG1 F243A, respectively. Fucosylation of HEK293-derived IgG1 F243A was maintained despite increased bisecting GlcNAc content. Although sialic acid and bisecting GlcNAc residues are reported to have an opposing effect on antibody-dependent cellular cytotoxicity (ADCC), IgG1 F243A showed 7 times lower ADCC activities than IgG1 WT, irrespective of bisecting GlcNAc residue. Thus, highly sialylated, human cell-derived IgG1 F243A with lowered ADCC activity may be of interest for the development of therapeutic antibodies with anti-inflammatory properties as an alternative to IVIG.
•Sialylation of IgG1-Fc is enhanced by F243A mutation.•The glycan structures of IgG1 F243A differ between the species of host cells.•Low ADCC activity of IgG1 F243A is not influenced by bisecting GlcNAc residue.•IgG1 F243A can be of interest for development as therapeutics.
Glycosylation as a marker for inflammatory arthritis Albrecht, Simone; Unwin, Louise; Muniyappa, Mohankumar ...
Cancer biomarkers : section A of Disease markers,
01/2014, Letnik:
14, Številka:
1
Journal Article
Recenzirano
Changes in serum protein glycosylation play an important role in inflammatory arthritis. Altered galactosylation of immunoglobulin G (IgG) in rheumatoid arthritis attracts special attention due to ...the devastating nature of the disease. Studying glycosylation changes of serum proteins has been recognized as a potential strategy to provide added value regarding diagnostics, aetiopathology and therapy of inflammatory arthritic diseases. Key questions, which are approached in these fields of research, are whether or not glycosylation can be used as a complementary pre-clinical and clinical marker for disease differentiation, diagnosis, the prediction of disease course and severity as well as for the evaluation of disease therapies. These studies mainly focus on TNF antagonists, which present a new and promising way of treating inflammatory arthritis. The recent availability of new high-throughput glycoanalytical tools enables a more profound and efficient investigation in large patient cohorts and helps to gain new insights in the complex mechanism of the underlying disease pathways.
The bacterium Neisseria meningitidis is commonly found harmlessly colonising the mucosal surfaces of the human nasopharynx. Occasionally strains can invade host tissues causing septicaemia and ...meningitis, making the bacterium a major cause of morbidity and mortality in both the developed and developing world. The species is known to be diverse in many ways, as a product of its natural transformability and of a range of recombination and mutation-based systems. Previous work on pathogenic Neisseria has identified several mechanisms for the generation of diversity of surface structures, including phase variation based on slippage-like mechanisms and sequence conversion of expressed genes using information from silent loci. Comparison of the genome sequences of two N. meningitidis strains, serogroup B MC58 and serogroup A Z2491, suggested further mechanisms of variation, including C-terminal exchange in specific genes and enhanced localised recombination and variation related to repeat arrays. We have sequenced the genome of N. meningitidis strain FAM18, a representative of the ST-11/ET-37 complex, providing the first genome sequence for the disease-causing serogroup C meningococci; it has 1,976 predicted genes, of which 60 do not have orthologues in the previously sequenced serogroup A or B strains. Through genome comparison with Z2491 and MC58 we have further characterised specific mechanisms of genetic variation in N. meningitidis, describing specialised loci for generation of cell surface protein variants and measuring the association between noncoding repeat arrays and sequence variation in flanking genes. Here we provide a detailed view of novel genetic diversification mechanisms in N. meningitidis. Our analysis provides evidence for the hypothesis that the noncoding repeat arrays in neisserial genomes (neisserial intergenic mosaic elements) provide a crucial mechanism for the generation of surface antigen variants. Such variation will have an impact on the interaction with the host tissues, and understanding these mechanisms is important to aid our understanding of the intimate and complex relationship between the human nasopharynx and the meningococcus.
Bordetella pertussis, Bordetella parapertussis and Bordetella bronchiseptica are closely related Gram-negative beta-proteobacteria that colonize the respiratory tracts of mammals. B. pertussis is a ...strict human pathogen of recent evolutionary origin and is the primary etiologic agent of whooping cough. B. parapertussis can also cause whooping cough, and B. bronchiseptica causes chronic respiratory infections in a wide range of animals. We sequenced the genomes of B. bronchiseptica RB50 (5,338,400 bp; 5,007 predicted genes), B. parapertussis 12822 (4,773,551 bp; 4,404 genes) and B. pertussis Tohama I (4,086,186 bp; 3,816 genes). Our analysis indicates that B. parapertussis and B. pertussis are independent derivatives of B. bronchiseptica-like ancestors. During the evolution of these two host-restricted species there was large-scale gene loss and inactivation; host adaptation seems to be a consequence of loss, not gain, of function, and differences in virulence may be related to loss of regulatory or control functions.
We determined the complete genome sequence of Clostridium difficile strain 630, a virulent and multidrug-resistant strain. Our analysis indicates that a large proportion (11%) of the genome consists ...of mobile genetic elements, mainly in the form of conjugative transposons. These mobile elements are putatively responsible for the acquisition by C. difficile of an extensive array of genes involved in antimicrobial resistance, virulence, host interaction and the production of surface structures. The metabolic capabilities encoded in the genome show multiple adaptations for survival and growth within the gut environment. The extreme genome variability was confirmed by whole-genome microarray analysis; it may reflect the organism's niche in the gut and should provide information on the evolution of virulence in this organism.
Rabbits are popular companion animals. There are numerous welfare issues affecting the majority of the population, including the fact that most rabbits are fearful when handled. Pet Remedy ™ (Unex ...Designs) is an herbal product containing valerian, marketed as a natural calming aid. Its efficacy for domestic rabbits is previously untested. We describe a randomized, double-blind, placebo-controlled trial into the effectiveness of Pet Remedy. Fifty rabbits underwent a baseline test followed by both a placebo and a Pet Remedy treatment. We measured rabbit’s behavior by a novel arena test, responses to the experimenter when in the home enclosure and when being handled, and heart and respiratory rates during handling. Repeated measures analysis of variance tested differences between treatments, taking into account rabbits’ individual baselines. Exposure to Pet Remedy was associated with a significant decrease in heart rate during handling (F(1,42) = 4.41, P = 0.042) and a significant increase in the number of positive behaviors observed in the novel arena (F(1,47) = 4.52, P = 0.039). Other variables which may have been predicted to change were unaffected. Rearing in the novel arena increased with day (F(1,45) = 6.91, P = 0.012). Significant individual variation occurred throughout, and heart rates were universally high suggesting that handling is generally an aversion to rabbits. The results suggest that Pet Remedy may have potential value for rabbits during periods of acute stress, slowing heart rate, and allowing the performance of more positive, relaxed behaviors. It may be useful during veterinary visits and initial handling. However, given the high levels of physiological and behavioral stress exhibited by rabbits, optimal handling and appropriate habituation and desensitization and counter-conditioning protocols should also be simultaneously implemented.
Because of advances in targeted therapies, the clinical evaluation of cutaneous melanoma is increasingly based on a combination of traditional histopathology and molecular pathology. Therefore, it is ...necessary to expand our knowledge of the molecular events that accompany the development and progression of melanoma to optimize clinical management. The central objective of this study was to increase our knowledge of the mutational events that complement melanoma progression. High-throughput genotyping was adapted to query 159 known single nucleotide mutations in 33 cancer-related genes across two melanoma cohorts from Ireland (n=94) and Belgium (n=60). Results were correlated with various clinicopathological characteristics. A total of 23 mutations in 12 genes were identified, that is--BRAF, NRAS, MET, PHLPP2, PIK3R1, IDH1, KIT, STK11, CTNNB1, JAK2, ALK, and GNAS. Unexpectedly, we discovered significant differences in BRAF, MET, and PIK3R1 mutations between the cohorts. That is, cases from Ireland showed significantly lower (P<0.001) BRAF(V600E) mutation rates (19%) compared with the mutation frequency observed in Belgian patients (43%). Moreover, MET mutations were detected in 12% of Irish cases, whereas none of the Belgian patients harbored these mutations, and Irish patients significantly more often (P=0.027) had PIK3R1-mutant (33%) melanoma versus 17% of Belgian cases. The low incidence of BRAF(V600E)(-) mutant melanoma among Irish patients was confirmed in five independent Irish cohorts, and in total, only 165 of 689 (24%) Irish cases carried mutant BRAF(V600E). Together, our data show that melanoma-driving mutations vary by demographic area, which has important implications for the clinical management of this disease.
Background: Aggressive behaviour exhibited by adults with intellectual disabilities (ID) can negatively affect the person and those around them. Aims: To longitudinally investigate the topography and ...trajectory of aggressive behaviour and to identify cross-sectional and prospective risk factors including personal characteristics, co-morbid conditions and contextual factors in a clinical cohort. Methods: Structured interviews with carers of 100 adults with ID who exhibit aggressive behaviour were conducted three times over 12 months, at six-month intervals. Questionnaires and standardised assessment scales were administered at each time point to assess aggressive behaviour, including triggers, other problem behaviour, quality of life, carer’s outcomes, mental health problems, physical health conditions and demographic variables. Results: Aggressive behaviour was long-standing, however, behaviour improved with 43% demonstrating a reliable improvement. A model of severity of aggressive behaviour accounted for 50-54% of the variance at follow-up. Those with more severe ID were over 3 times more likely to exhibit self-injurious behaviour and females were over 5 times more likely to exhibit verbal aggression. Carers implicated a wide range of contextual variables as triggers for aggressive behaviour. Conclusions: A clinical profile of topography of aggressive behaviour, including risk factor profile among adults with ID may guide interventions and inform service provision.
Current prescribing preferences among relevant experts regarding the use of psychotropic medication for the management of behavior problems in adults with intellectual disabilities in the absence of ...a diagnosed psychiatric illness was defined. We used a questionnaire design to synthesize the preferences of a large group, namely, clinical psychiatrists, thereby establishing a consensus. A total of 108 completed questionnaires were analyzed. A very strong preference for the use of nonmedication-based interventions was established. Of the medication options presented, atypical antipsychotics were most favored, with Risperidone the most preferred option from within this group. Citalopram was the most preferred antidepressant and Carbamazepine, the most preferred mood stabilizer/antiepileptic.
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