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Dominant Clone (dominant + clone)
Selected AbstractsIdentification and Repair of Positive Binding Antibodies Containing Randomly Generated Amber Codons from Synthetic Phage Display LibrariesBIOTECHNOLOGY PROGRESS, Issue 3 2006Warren D. Marcus Phage display technology allows for the rapid isolation and characterization of monoclonal antibodies that have vast potential for therapeutic and diagnostic applications. However, the panning process, which utilizes a host strain that suppresses termination by the amber codon, has an inherent bias toward clones containing randomly generated amber stop codons, complicating identification of positive binding antibodies when the antibody genes are finally expressed in a nonsupressor host. Here, we perform biopanning against a Histone 2A peptide using streptavidin- or anti-biotin-coated beads. After four rounds, a dominant clone is characterized but contains a spurious amber stop codon. A protocol is given that readily corrects the amber codon, allowing for soluble antibody production once the phagemid is transformed into a nonsuppressor bacterial strain. This work also highlights the ability to isolate antibodies against a protein antigen by using only a small peptide (15 amino acids) representing a portion of the antigen. [source] The presence of dominant T-cell clones in peripheral blood of patients with collagen vascular disorders: a prospective study of 97 casesBRITISH JOURNAL OF DERMATOLOGY, Issue 3 2006O. Dereure Summary Background, T-lymphocyte dysfunction has been seldom investigated in collagen vascular disorders. The search for dominant T-cell clones has been scarcely reported, although the presence of such clones might be expected in disorders showing immune responses directed against a variety of autoantigens. Objectives, We conducted a systematic search for dominant T-cell clones in peripheral blood in patients with collagen vascular disorders. Patients and methods, Ninety-seven patients with collagen vascular disorders were studied (7 cutaneous and 38 systemic lupus erythematosus; 8 multiple morphea; 12 regional scleroderma; 32 systemic sclerosis of the CREST type). A dominant T-cell clone was searched for in peripheral blood by polymerase chain reaction targeting the T-cell receptor , chain followed by a size analysis of amplified fragments. Peripheral blood from patients with nonlymphocyte-dependent disorders and matched by age and sex was assessed in the same conditions. Results in both groups were compared using nonparametric statistical tests. Results, Overall, a circulating dominant T-cell clone was found in 52% of patients compared with 16·9% in controls. More precisely, such a dominant clone was present in 43% and 37% of cutaneous and systemic lupus erythematosus, respectively, in 75% of multiple morphea, 75% of regional scleroderma and 60% of CREST syndrome patients. The percentages in all subsets of patients were significantly higher than in the control group. Conclusions, The presence of a dominant T-cell clone in peripheral blood is significantly more frequent in collagen vascular disorders than in controls, especially in patients with scleroderma, whatever the clinical subset, which suggests T-cell involvement in the immune response dysfunction in these diseases classically characterized by disturbances of B lymphocytes. The relevance of such a dominant clone regarding diagnosis, pathomechanisms, long-term outcome and visceral prognosis of these diseases as well as therapeutic decisions remains to be evaluated. [source] Evidence for allelic evolution of C/EBPalpha mutations in acute myeloid leukaemiaBRITISH JOURNAL OF HAEMATOLOGY, Issue 3 2003Jens Tiesmeier Summary. Transcription factor CCAAT/enhancer binding protein , (C/EBP,) is mutated in 6,10% of patients with acute myeloid leukaemia (AML). Recently, we reported the emergence of an N-terminal C/EBP, mutation after chemotherapy in a patient with secondary AML. The clone carrying the mutation became the dominant clone at relapse. This observation prompted us to compare the C/EBP, mutational status of 26 de novo non-core binding factor AML patients at diagnosis and at relapse after induction and consolidation chemotherapy. Four mutations in the C/EBP, gene were identified in two out of 26 patients. In both these cases, a biallelic mutation was present at diagnosis and at relapse: an amino-terminal frameshift mutation and a mutation of the fork/leucine finger 1 region. In patient 1, the amino-terminal frameshift mutation was duplicated and found on both alleles at relapse. In patient 2, the amino-terminal frameshift mutation and a mutation in the fork region were found either alone or combined on the same allele, suggesting a subclone formation. None of the patients without a C/EBP, mutation at diagnosis showed a mutation at relapse. This is the first report of an evolution of the C/EBP, gene between diagnosis and relapse in AML. [source] Distinct ribotypes and rates of antimicrobial drug resistance in Clostridium difficile from Shanghai and StockholmCLINICAL MICROBIOLOGY AND INFECTION, Issue 12 2009H. Huang Abstract Seventy-five clinical isolates of Clostridium difficile from Shanghai and 80 from Stockholm were investigated. The prevalence of toxin A-negative, toxin B-positive isolates of C. difficile among isolates from Shanghai (33.3%) was significantly higher than among isolates from Stockholm (0%). Both sets of isolates were fully susceptible to metronidazole and vancomycin. However, the MICs of fluoroquinolones, erythromycin,clindamycin, tetracycline, rifampin and fusidic acid were significantly higher for the Shanghai isolates than for the Stockholm isolates. Thirty-three PCR ribotypes were identified; a dominant clone, 017, accounted for 18.7% of Shanghai isolates, whereas clone 005 dominated among Stockholm isolates, accounting for 11.3%. Strains 027 and 078 were not detected. No outbreak occurred during the study period. [source] | ||||||||||