RESUMEN
Scratching is an important factor exacerbating skin lesions through the so-called itch-scratch cycle in atopic dermatitis (AD). In mice, interleukin (IL)-31 and its receptor IL-31 receptor A (IL-31RA) are known to play a critical role in pruritus and the pathogenesis of AD; however, study of their precise roles in primates is hindered by the low sequence homologies between primates and mice and the lack of direct evidence of itch sensation by IL-31 in primates. We showed that administration of cynomolgus IL-31 induces transient scratching behaviour in cynomolgus monkeys and by that were able to establish a monkey model of scratching. We then showed that a single subcutaneous injection of 1 mg/kg nemolizumab, a humanized anti-human IL-31RA monoclonal antibody that also neutralizes cynomolgus IL-31 signalling and shows a good pharmacokinetic profile in cynomolgus monkeys, suppressed the IL-31-induced scratching for about 2 months. These results suggest that the IL-31 axis and IL-31RA axis play as critical a role in the induction of scratching in primates as in mice and that the blockade of IL-31 signalling by an anti-human IL-31RA antibody is a promising therapeutic approach for treatment of AD. Nemolizumab is currently under investigation in clinical trials.
Asunto(s)
Anticuerpos Monoclonales Humanizados/farmacología , Interleucinas/farmacología , Prurito/inducido químicamente , Receptores de Interleucina/metabolismo , Células A549 , Animales , Células CHO , Línea Celular , Cricetulus , ADN Complementario/metabolismo , Humanos , Cinética , Macaca fascicularis , Masculino , Ratones , Prurito/metabolismo , Transducción de Señal , Piel/inmunología , Piel/patología , Enfermedades de la Piel/inmunología , Enfermedades de la Piel/patologíaRESUMEN
Agonistic diabodies that mimic the function of natural ligands are expected to increase the value of therapeutic antibodies. We have developed a method that detects agonistic diabodies based on their ability to transduce growth signals through receptors, thereby permitting cytokine-independent growth of BaF/3-derived cytokine-dependent cells. Retrovirus-mediated expression of the diabody in cytokine-dependent cells was followed by selection of clones for growth in the absence of cytokine. A diabody library derived from splenocytes of human Mpl immunized mice was constructed. Infection of cells with viral particles led to the isolation of over 500 autonomously growing clones whose cultured supernatants showed agonistic activities against Mpl. Genome-integrated diabodies were cloned; representative clone AB317 showed agonistic activities as potent as a natural ligand and cross-reactive against mouse Mpl.
Asunto(s)
Anticuerpos/metabolismo , Comunicación Autocrina , Proliferación Celular , Células Precursoras de Linfocitos B/inmunología , Receptores de Trombopoyetina/inmunología , Transducción de Señal , Secuencia de Aminoácidos , Animales , Anticuerpos/genética , Sitios de Unión de Anticuerpos , Células COS , Chlorocebus aethiops , Clonación Molecular , Biblioteca de Genes , Humanos , Inmunización , Cadenas Pesadas de Inmunoglobulina/biosíntesis , Cadenas Pesadas de Inmunoglobulina/genética , Cadenas Ligeras de Inmunoglobulina/biosíntesis , Cadenas Ligeras de Inmunoglobulina/genética , Región Variable de Inmunoglobulina/biosíntesis , Región Variable de Inmunoglobulina/genética , Interleucina-3/metabolismo , Ligandos , Ratones , Ratones Mutantes , Datos de Secuencia Molecular , Receptores de Trombopoyetina/agonistas , Receptores de Trombopoyetina/genética , Receptores de Trombopoyetina/metabolismo , Proteínas Recombinantes de Fusión/biosíntesis , Trombopoyetina/metabolismo , TransfecciónRESUMEN
To characterize the biological activity of tocilizumab, a humanized anti-human interleukin-6 receptor (IL-6R) monoclonal antibody, we examined its binding activity to both soluble IL-6R (sIL-6R) and membrane bound IL-6R (mIL-6R) and its neutralizing activity to other IL-6 family cytokines. ELISA assay demonstrated that tocilizumab bound to sIL-6R and inhibited IL-6 binding to sIL-6R in a dose-dependent manner. The dissociation constant (Kd value) for IL-6R was determined to be 2.54+/-0.12 nmol/L by Scatchard analysis. In addition, tocilizumab had the ability to dissociate IL-6 and sIL-6R from their preformed complex. The immune complex of tocilizumab and sIL-6R did not transmit signaling. Moreover, tocilizumab suppressed the IL-6/sIL-6R complex-induced proliferation of human gp130-transfected cell, BAF-h130. In addition, tocilizumab had the ability to bind to human IL-6R expressing COS-7 cells and to suppress the growth of the IL-6-dependent myeloma cell line, KPMM2. Finally, to analyze the specificity of this antibody, the effects on signal transduction of IL-6 family cytokines such as interleukin-11 (IL-11), oncostatin M (OSM), leukemia inhibitory factor (LIF), and ciliary neurotrophic factor (CNTF) were examined using murine transfectant cell lines (BaF/IL-6R, BaF/IL-11R, BaF/OSMR, BaF/LIFR and BaF/CNTFR) that proliferate depending on IL-6, IL-11, OSM, LIF and human CNTF, respectively. Tocilizumab inhibited the proliferation of BaF/IL-6R induced by IL-6, but did not inhibit the proliferation of BaF/IL-11R, BaF/OSMR, BaF/LIFR and BaF/CNTFR cells induced by their corresponding cytokines. These lines of evidence indicate that tocilizumab is able to bind to both sIL-6R and mIL-6R and to inhibit IL-6 binding to its receptors, leading to the blockade of the IL-6 signaling through both sIL-6R and mIL-6R, but not block the signaling of other IL-6 family cytokines.
