The Experts below are selected from a list of 113751 Experts worldwide ranked by ideXlab platform
Gabor Z Racz - One of the best experts on this subject based on the ideXlab platform.
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in vivo secretion of the mouse Immunoglobulin g fc fragment from rat submandibular glands
Journal of Gene Medicine, 2009Co-Authors: Gabor Z Racz, Paola Perezriveros, Janik Adriaansen, Changyu Zheng, Bruce J BaumAbstract:Background—Salivary glands have been proposed as target organs for gene therapy. They secrete endogenous, as well as transgenic proteins, in a polarized manner. Transgene-encoded regulated pathway proteins primarily follow the regulated pathway in rat salivary glands and are secreted into saliva in an exocrine manner. Conversely, constitutive pathway proteins generally are secreted more basolaterally and thus follow the endocrine route. In the present study, we studied in vivo the sorting of the mouse Immunoglobulin G2b Fc fragment, which is physiologically secreted via the constitutive pathway. Methods—Adenoviral vectors encoding the Fc fragment and human growth hormone were delivered into rat and mouse submandibular glands in vivo to compare their serum-to-saliva distribution. We also compared the intracellular localization of the Fc fragment and growth hormone by confocal microscopy. Results—We found that the Fc fragment was secreted almost entirely into the bloodstream from rat and mouse submandibular glands via a constitutive or constitutive-like pathway. This sorting behaviour is clearly different from that of transgenic human growth hormone, which is secreted in a regulated pathway, both in neuroendocrine cells and as a transgenic protein from salivary gland cells. We also found that simultaneously expressed human growth hormone and the mouse Fc fragment do not appear to influence each other's sorting behaviour. The Fc fragment showed a primarily basal localization, whereas growth hormone showed an apical localization, in rat submandibular gland acinar cells. Conclusions—The results obtained in the present study indicate that the mouse Fc fragment is a useful model protein for examining the basolateral versus apical secretory pathways employed by transgenic secretory proteins in salivary glands.
Koichi Kato - One of the best experts on this subject based on the ideXlab platform.
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nmr assignments of the n glycans of the fc fragment of mouse Immunoglobulin G2b glycoprotein
Biomolecular Nmr Assignments, 2021Co-Authors: Saeko Yanaka, Rina Yogo, Yoshiki Yamaguchi, Takeshi Takizawa, Yohei Miyanoiri, Ichio Shimada, Koichi KatoAbstract:The Fc portion of Immunoglobulin G (IgG) promotes defensive effector functions in the immune system by interacting with Fcγ receptors and complement component C1q. These interactions critically depend on N-glycosylation at Asn297 of each CH2 domain, where biantennary complex-type oligosaccharides contain microheterogeneities resulting primarily from the presence or absence of non-reducing terminal galactose residues. Crystal structures of Fc have shown that a pair of N-glycans is located between the two CH2 domains. Here we applied our metabolic isotope labeling technique using mammalian cells for in-solution structural characterization of mouse IgG2b-Fc glycoforms with a molecular mass of 54 kDa. Based on spectral assignments of the N-glycans as well as polypeptide backbones of Fc, we probed conformational perturbations of Fc induced by N-glycan trimming, especially enzymatic degalactosylation. The results indicated that degalactosylation structurally perturbed the Fc region through rearrangement of glycan-protein interactions. The spectral assignments of IgG2b-Fc glycoprotein will provide the basis for NMR investigation of its dynamic conformations and interactions with effector molecules in solution.
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mutational deglycosylation of the fc portion of Immunoglobulin g causes o sulfation of tyrosine adjacently preceding the originally glycosylated site
FEBS Letters, 2010Co-Authors: Katsuyoshi Masuda, Yoshiki Yamaguchi, Noriko Takahashi, R Jefferis, Koichi KatoAbstract:Mutagenesis directed to a specific glycosylation site has been widely used to examine biological roles of individual glycans. However, occurrence of any post-translational modification on such deglycosylated mutants has not yet been well characterized. Here we performed mass spectrometric analyses of the Fc fragment of an unglycosylated mutant of mouse Immunoglobulin G2b, whose conserved N-glycosylation site, i.e. Asn297, was substituted with alanine. We found that a major part of this mutant is sulfated at Tyr296, which adjacently precedes the originally glycosylated site. Our findings demonstrate that mutational deglycosylation can induce an unexpected post-translational modification in the protein.
Sven Lodziewski - One of the best experts on this subject based on the ideXlab platform.
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Treatment of malignant pleural effusion with the trifunctional antibody catumaxomab (Removab) (anti-EpCAM x Anti-CD3): results of a phase 1/2 study.
Journal of immunotherapy (Hagerstown Md. : 1997), 2009Co-Authors: Martin Sebastian, Philipp Kiewe, Wolfgang Schuette, Daniel Brust, Christian Peschel, Folker Schneller, Karl-heinz Rühle, Georg Nilius, Ralf Ewert, Sven LodziewskiAbstract:Catumaxomab is a trifunctional monoclonal antibody consisting of a mouse Immunoglobulin G2a part and a rat Immunoglobulin G2b part with 2 different antigen binding sites binding the epithelial cell adhesion molecule antigen on tumor cells and CD3 on T lymphocytes. The intact Fc region provides a third functional binding site, binding and activating selectively Fcgamma receptor I, IIa, and III-positive accessory cells. These binding properties lead to specific tumor cell killing. As catumaxomab demonstrated efficacy in patients with malignant ascites, we performed this phase 1/2 trial in patients with malignant pleural effusion (MPE). We investigated a series of 3 escalating doses of 5 to 200 microg catumaxomab administered intrapleurally to patients with MPE containing epithelial cell adhesion molecule -positive cells. Primary objectives were determination of dose-limiting toxicity, safety, and tolerability. Secondary objectives were efficacy and pharmacodynamics. Twenty-four patients were treated with catumaxomab. Most frequent adverse events were pyrexia, elevated liver enzymes, nausea, and decreased lymphocytes. Dose-limiting toxicities were observed in 2 patients: One had pleural empyema and fatal sepsis and 1 had grade 3 erythema and hepatobiliary disorder. Five patients with breast cancer out of 7 evaluable patients had a response to treatment. Intrapleural administration of catumaxomab is feasible although the substantial number of drop-outs and deaths in short proximity to study treatment raise questions whether MPE is the right indication for catumaxomab or whether the patient population should be defined different. Safety profile was as expected reflecting catumaxomab's mode of action. Preliminary efficacy showed a suggestion of improvement in some patients.
Bruce J Baum - One of the best experts on this subject based on the ideXlab platform.
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in vivo secretion of the mouse Immunoglobulin g fc fragment from rat submandibular glands
Journal of Gene Medicine, 2009Co-Authors: Gabor Z Racz, Paola Perezriveros, Janik Adriaansen, Changyu Zheng, Bruce J BaumAbstract:Background—Salivary glands have been proposed as target organs for gene therapy. They secrete endogenous, as well as transgenic proteins, in a polarized manner. Transgene-encoded regulated pathway proteins primarily follow the regulated pathway in rat salivary glands and are secreted into saliva in an exocrine manner. Conversely, constitutive pathway proteins generally are secreted more basolaterally and thus follow the endocrine route. In the present study, we studied in vivo the sorting of the mouse Immunoglobulin G2b Fc fragment, which is physiologically secreted via the constitutive pathway. Methods—Adenoviral vectors encoding the Fc fragment and human growth hormone were delivered into rat and mouse submandibular glands in vivo to compare their serum-to-saliva distribution. We also compared the intracellular localization of the Fc fragment and growth hormone by confocal microscopy. Results—We found that the Fc fragment was secreted almost entirely into the bloodstream from rat and mouse submandibular glands via a constitutive or constitutive-like pathway. This sorting behaviour is clearly different from that of transgenic human growth hormone, which is secreted in a regulated pathway, both in neuroendocrine cells and as a transgenic protein from salivary gland cells. We also found that simultaneously expressed human growth hormone and the mouse Fc fragment do not appear to influence each other's sorting behaviour. The Fc fragment showed a primarily basal localization, whereas growth hormone showed an apical localization, in rat submandibular gland acinar cells. Conclusions—The results obtained in the present study indicate that the mouse Fc fragment is a useful model protein for examining the basolateral versus apical secretory pathways employed by transgenic secretory proteins in salivary glands.
Martin Sebastian - One of the best experts on this subject based on the ideXlab platform.
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Treatment of malignant pleural effusion with the trifunctional antibody catumaxomab (Removab) (anti-EpCAM x Anti-CD3): results of a phase 1/2 study.
Journal of immunotherapy (Hagerstown Md. : 1997), 2009Co-Authors: Martin Sebastian, Philipp Kiewe, Wolfgang Schuette, Daniel Brust, Christian Peschel, Folker Schneller, Karl-heinz Rühle, Georg Nilius, Ralf Ewert, Sven LodziewskiAbstract:Catumaxomab is a trifunctional monoclonal antibody consisting of a mouse Immunoglobulin G2a part and a rat Immunoglobulin G2b part with 2 different antigen binding sites binding the epithelial cell adhesion molecule antigen on tumor cells and CD3 on T lymphocytes. The intact Fc region provides a third functional binding site, binding and activating selectively Fcgamma receptor I, IIa, and III-positive accessory cells. These binding properties lead to specific tumor cell killing. As catumaxomab demonstrated efficacy in patients with malignant ascites, we performed this phase 1/2 trial in patients with malignant pleural effusion (MPE). We investigated a series of 3 escalating doses of 5 to 200 microg catumaxomab administered intrapleurally to patients with MPE containing epithelial cell adhesion molecule -positive cells. Primary objectives were determination of dose-limiting toxicity, safety, and tolerability. Secondary objectives were efficacy and pharmacodynamics. Twenty-four patients were treated with catumaxomab. Most frequent adverse events were pyrexia, elevated liver enzymes, nausea, and decreased lymphocytes. Dose-limiting toxicities were observed in 2 patients: One had pleural empyema and fatal sepsis and 1 had grade 3 erythema and hepatobiliary disorder. Five patients with breast cancer out of 7 evaluable patients had a response to treatment. Intrapleural administration of catumaxomab is feasible although the substantial number of drop-outs and deaths in short proximity to study treatment raise questions whether MPE is the right indication for catumaxomab or whether the patient population should be defined different. Safety profile was as expected reflecting catumaxomab's mode of action. Preliminary efficacy showed a suggestion of improvement in some patients.
