Multivalent Fc?-receptor engagement by a hexameric Fc-fusion protein triggers Fc?-receptor internalisation and modulation of Fc?-receptor functions.

ABSTRACT: Engagement of Fc?-receptors triggers a range of downstream signalling events resulting in a diverse array of immune functions. As a result, blockade of Fc-mediated function is an important strategy for the control of several autoimmune and inflammatory conditions. We have generated a hexameric-Fc fusion protein (hexameric-Fc) and tested the consequences of multi-valent Fc?-receptor engagement in in vitro and in vivo systems. In vitro engagement of hexameric-Fc with Fc?Rs showed complex binding interactions that altered with receptor density and triggered the internalisation and degradation of Fc?-receptors. This caused a disruption of Fc-binding and phagocytosis. In vivo, in a mouse ITP model we observed a short half-life of hexameric-Fc but were nevertheless able to observe inhibition of platelet phagocytosis several days after hexameric-Fc dosing. In cynomolgus monkeys, we again observed a short half-life, but were able to demonstrate effective Fc?R blockade. These findings demonstrate the ability of multi-valent Fc-based therapeutics to interfere with Fc?R function and a potential mechanism through which they could have a sustained effect; the internalisation and degradation of Fc?Rs.

SUBMITTER: Qureshi OS 

PROVIDER: S-EPMC5719016 | biostudies-literature | 2017 Dec

REPOSITORIES: biostudies-literature