title: The activation and differential signalling of the growth hormone receptor induced by pGH or anti-idiotypic monoclonal antibodies in primary rat hepatocytes.
abstract: In this report, we have developed a panel of monoclonal anti-idiotypic antibodies to pGH by immunising BALB/c mice with a purified monoclonal anti-pGH antibody (1A3), among which one mAb, termed CG-8F, was selected for further characterisation. We found that CG-8F behaved as a typical Ab2β, not only conformationally competing with pGH for 1A3 but also exhibiting recognition for GHR in a rat hepatocyte model. We next examined the resulting signal transduction pathways triggered by this antibody in rat hepatocytes and found that both pGH and CG-8F could trigger the JAK2-STAT1/3/5-mediated signal transduction pathway. Furthermore, the phosphorylation kinetics of pSTAT1/3/5 induced by either pGH or CG-8F were remarkably similar in the dose-response and time course rat hepatocyte experiments. In contrast, only pGH, but not CG-8F, was capable of inducing ERK phosphorylation. Further experimental studies indicated that the two functional binding sites on CG-8F are required for GHR activation. This study partially reveals the mechanism of action of GH anti-idiotypic antibodies and also indicates that monoclonal anti-idiotypic antibodies represent an effective way to produce GH mimics, suggesting that it is possible to produce signal-specific cytokine agonists using an anti-idiotypic antibody approach.
authors.affiliation: College of Animal Science and Technology, Jilin Agricultural University, Changchun 130118, PR China.
authors.forename: Wei
authors.initials: W
authors.lastname: Li
authors.forename: Hainan
authors.initials: H
authors.lastname: Lan
authors.forename: Huimin
authors.initials: H
authors.lastname: Liu
authors.forename: Zhiling
authors.initials: Z
authors.lastname: Fu
authors.forename: Yanhong
authors.initials: Y
authors.lastname: Yang
authors.forename: Weiwei
authors.initials: W
authors.lastname: Han
authors.forename: Feng
authors.initials: F
authors.lastname: Guo
authors.forename: Yu
authors.initials: Y
authors.lastname: Liu
authors.forename: Hui
authors.initials: H
authors.lastname: Zhang
authors.forename: Jingsheng
authors.initials: J
authors.lastname: Liu
authors.forename: Xin
authors.initials: X
authors.lastname: Zheng
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D000888:Antibodies, Anti-Idiotypic / Q000096:biosynthesis / Q000302:isolation & purification / Q000494:pharmacology*; D000911:Antibodies, Monoclonal / Q000096:biosynthesis / Q000302:isolation & purification / Q000494:pharmacology*; D005786:Gene Expression Regulation; D013006:Growth Hormone / Q000378:metabolism* / Q000494:pharmacology; D022781:Hepatocytes / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D053614:Janus Kinase 2 / Q000235:genetics / Q000378:metabolism; D008099:Liver / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D010766:Phosphorylation; D061251:Primary Cell Culture; D051381:Rats; D017208:Rats, Wistar; D011986:Receptors, Somatotropin / Q000235:genetics* / Q000378:metabolism; D050794:STAT1 Transcription Factor / Q000235:genetics / Q000378:metabolism; D050796:STAT3 Transcription Factor / Q000235:genetics / Q000378:metabolism; D050799:STAT5 Transcription Factor / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects*
chemical_list: D000888:Antibodies, Anti-Idiotypic; D000911:Antibodies, Monoclonal; D011986:Receptors, Somatotropin; D050794:STAT1 Transcription Factor; D050796:STAT3 Transcription Factor; D050799:STAT5 Transcription Factor; C494081:Stat1 protein, rat; C494088:Stat3 protein, rat; D013006:Growth Hormone; C507927:Jak2 protein, rat; D053614:Janus Kinase 2
keywords: Ab2; Anti-idiotypic monoclonal antibody; CLSM; FITC; GHR; Growth hormone; JAK; Janus kinase; MAPK; PBS; PRL; STAT; Signal transduction; TMB; TPO; anti-idiotypic antibody; confocal laser scanning microscope; fluorescein isothiocyanate; growth hormone receptor; mAb; mitogen-activated protein kinase; monoclonal antibody; pGH; phosphate-buffered saline; porcine growth hormone; prolactin; signal transducers and activators of transcription; tetramethylbenzidine; thrombopoietin