RESUMEN
Myeloid-derived suppressor cells (MDSCs) are immature myeloid cells critical in mediating immune suppression in cancer patients. To develop an in vitro assay system that functionally mimics the tumor microenvironment, we cultured human monocytes with conditioned media from several cancer cell lines. Conditioned media from five tumor cell lines induced survival and differentiation of monocytes into cells characteristically similar to macrophages and MDSCs. Notably, media from the 786.O renal cell carcinoma line induced monocytes to acquire a monocytic MDSC phenotype characterized by decreased HLA-DR expression, increased nitric oxide production, enhanced proliferation, and ability to suppress autologous CD3+ T cell proliferation. We further demonstrated that these in vitro MDSCs are phenotypically and functionally similar to patient-derived MDSCs. Inhibitors of STAT3, CK2, and GM-CSF resulted in partial reversal of the MDSC phenotype. MDSCs generated in vitro from 786.O tumor conditioned media represent a platform to identify potential therapeutics that inhibit MDSC activities.
Asunto(s)
Carcinoma de Células Renales/metabolismo , Técnicas de Cocultivo/métodos , Monocitos/efectos de los fármacos , Células Supresoras de Origen Mieloide/efectos de los fármacos , Diferenciación Celular/efectos de los fármacos , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Medios de Cultivo Condicionados , Humanos , Activación de Linfocitos , Modelos Biológicos , Monocitos/citología , Monocitos/inmunología , Células Mieloides/citología , Células Mieloides/efectos de los fármacos , Células Mieloides/inmunología , Células Supresoras de Origen Mieloide/citología , Células Supresoras de Origen Mieloide/inmunología , Fenotipo , Microambiente Tumoral/fisiologíaRESUMEN
Bispecific antibodies (bsAbs) present an attractive opportunity to combine the additive and potentially synergistic effects exhibited by combinations of monoclonal antibodies (mAbs). Current challenges for engineering bsAbs include retention of the binding affinity of the parent mAb or antibody fragment, the ability to bind both targets simultaneously, and matching valency with biology. Other factors to consider include structural stability and expression of the recombinant molecule, both of which may have significant impact on its development as a therapeutic. Here, we incorporate selection of stable, potent single-chain variable fragments (scFvs) early in the engineering process to assemble bsAbs for therapeutic applications targeting the cytokines IL-17A/A and IL-23. Stable scFvs directed against human cytokines IL-23p19 and IL-17A/A were isolated from a human Fab phage display library via batch conversion of panning output from Fabs to scFvs. This strategy integrated a step for shuffling V regions during the conversion and permitted the rescue of scFv molecules in both the V(H)V(L) and the V(L)V(H) orientations. Stable scFvs were identified and assembled into several bispecific formats as fusions to the Fc domain of human IgG1. The engineered bsAbs are potent neutralizers of the biological activity of both cytokines (IC(50) < 1 nM), demonstrate the ability to bind both target ligands simultaneously and display stability and productivity advantageous for successful manufacture of a therapeutic molecule. Pharmacokinetic analysis of the bsAbs in mice revealed serum half-lives similar to human mAbs. Assembly of bispecific molecules using stable antibody fragments offers an alternative to reformatting mAbs and minimizes subsequent structure-related and manufacturing concerns.
Asunto(s)
Anticuerpos Biespecíficos/genética , Anticuerpos Biespecíficos/inmunología , Interleucina-17/inmunología , Interleucina-23/inmunología , Ingeniería de Proteínas , Animales , Anticuerpos Biespecíficos/química , Anticuerpos Biespecíficos/farmacocinética , Anticuerpos Monoclonales/química , Anticuerpos Monoclonales/inmunología , Afinidad de Anticuerpos , Bases de Datos de Proteínas , Escherichia coli/genética , Femenino , Semivida , Humanos , Cinética , Ratones , Estabilidad Proteica , Anticuerpos de Cadena Única/química , Anticuerpos de Cadena Única/genética , Anticuerpos de Cadena Única/inmunología , Anticuerpos de Cadena Única/metabolismoRESUMEN
The proinflammatory cytokines IL-17A and IL-17F have a high degree of sequence similarity and share many biological properties. Both have been implicated as factors contributing to the progression of inflammatory and autoimmune diseases. Moreover, reagents that neutralize IL-17A significantly ameliorate disease severity in several mouse models of human disease. IL-17A mediates its effects through interaction with its cognate receptor, the IL-17 receptor (IL-17RA). We report here that the IL-17RA-related molecule, IL-17RC is the receptor for IL-17F. Notably, both IL-17A and IL-17F bind to IL-17RC with high affinity, leading us to suggest that a soluble form of this molecule may serve as an effective therapeutic antagonist of IL-17A and IL-17F. We generated a soluble form of IL-17RC and demonstrate that it effectively blocks binding of both IL-17A and IL-17F, and that it inhibits signaling in response to these cytokines. Collectively, our work indicates that IL-17RC functions as a receptor for both IL-17A and IL-17F and that a soluble version of this protein should be an effective antagonist of IL-17A and IL-17F mediated inflammatory diseases.
Asunto(s)
Interleucina-17/metabolismo , Receptores de Interleucina-17/metabolismo , Empalme Alternativo/inmunología , Animales , Unión Competitiva/inmunología , Línea Celular , Cricetinae , Humanos , Mediadores de Inflamación/metabolismo , Mediadores de Inflamación/uso terapéutico , Interleucina-17/antagonistas & inhibidores , Ratones , Ratones Endogámicos BALB C , Datos de Secuencia Molecular , Unión Proteica/genética , Unión Proteica/inmunología , Receptores de Interleucina-17/genética , Receptores de Interleucina-17/uso terapéutico , Especificidad de la Especie , TransfecciónRESUMEN
Corticotroph-derived glycoprotein hormone (CGH), also referred to as thyrostimulin, is a noncovalent heterodimer of glycoprotein hormone alpha 2 (GPHA2) and glycoprotein hormone beta 5 (GPHB5). Here, we demonstrate that both subunits of CGH are expressed in the corticotroph cells of the human anterior pituitary, as well as in skin, retina, and testis. CGH activates the TSH receptor (TSHR); (125)I-CGH binding to cells expressing TSHR is saturable, specific, and of high affinity. In competition studies, unlabeled CGH is a potent competitor for (125)I-TSH binding, whereas unlabeled TSH does not compete for (125)I-CGH binding. Binding and competition analyses are consistent with the presence of two binding sites on the TSHR transfected baby hamster kidney cells, one that can interact with either TSH or CGH, and another that binds CGH alone. Transgenic overexpression of GPHB5 in mice produces elevations in serum T(4) levels, reductions in body weight, and proptosis. However, neither transgenic overexpression of GPHA2 nor deletion of GPHB5 produces an overt phenotype in mice. In vivo administration of CGH to mice produces a dose-dependent hyperthyroid phenotype including elevation of T(4) and hypertrophy of cells within the inner adrenal cortex. However, the distinctive expression patterns and binding characteristics of CGH suggest that it has endogenous biological roles that are discrete from those of TSH.