Woods, G. | Search bioRxiv

bioRxiv2021

EROS-mediated control of NOX2 and P2X7 biosynthesis

EROS (Essential for Reactive Oxygen Species) protein is indispensable for expression of gp91phox, the catalytic core of the phagocyte NADPH oxidase. EROS deficiency in humans is a novel cause of the severe immunodeficiency, chronic granulomatous disease (CGD), but its mechanism of action was unknown until now. We elucidate the role of EROS, showing it acts at the earliest stages of gp91phox maturation. It binds the immature 58kDa gp91phox directly, preventing gp91phox degradation and allowing glycosylation via the oligosaccharyltransferase (OST) machinery and the incorporation of the heme prosthetic groups essential for catalysis. EROS also regulates the purine receptors P2X7 and P2X1 through direct interactions and P2X7 is almost absent in EROS deficient mouse and human primary cells. Accordingly, lack of EROS results in markedly abnormal P2X7 signalling, inflammasome activation and T cell responses. The loss of both ROS and P2X7 signalling leads to resistance to influenza infection. Our work identifies EROS as a highly selective chaperone for key proteins in innate and adaptive immunity and a rheostat for immunity to infection. It has profound implications for our understanding of immune physiology, ROS dysregulation and possibly gene therapy.

immunology↗

bioRxiv2020

Post release immune responses of Tasmanian devils vaccinated with an experimental devil facial tumour disease vaccine

Disease is increasingly becoming a driver of wildlife population declines and extinction risk. Vaccines have been one of the most successful health interventions in human history, but few have been tested for mitigating wildlife disease. The transmissible cancer, devil facial tumour disease (DFTD), triggered the Tasmanian devils (Sarcophilus harrisii) inclusion on the international endangered species list. Development of a protective DFTD vaccine would provide a valuable management approach for conservation of the species. In 2016, 33 devils from a DFTD-free insurance population were given an experimental DFTD vaccination prior to their release on the north coast of Tasmania. The release site was already home to an incumbent population of devils, including some individuals with DFTD. To determine the efficacy of the vaccination protocol and the longevity of the response it induced, six trapping trips took place at the site over the 2.5 years following release. Eight of the 33 vaccinated devils were re-trapped, and six of those developed DFTD within the monitoring period. Despite the apparent lack of protection provided by the vaccine for the re-trapped devils, we observed several signs of immune activation not usually found in unvaccinated devils. Firstly, sera collected from the eight devils showed that anti-DFTD antibodies persisted for up to two years post vaccination. Secondly, tumour infiltrating lymphocytes were found in three out of four biopsies collected from vaccinated devils which contrasts with the "immune deserts" typical of DFTs; only one out of twenty incumbent devils with DFTD trapped during the same period had a tumour biopsy exhibiting immune cell infiltrate. Thirdly, immunohistochemical analysis of tumour biopsies from the vaccinated devils identified the functional immune molecules associated with antigen presenting cells (MHC-II) and T cells (CD3), and the immune checkpoint molecule PD-1, all associated with anti-tumour immunity in other species. These results correlate with our previous study on captive devils in which a prophylactic vaccine primed the devil immune system and, following DFTD challenge and tumour growth, immunotherapy induced complete tumour regressions. The field trial results presented here provide further evidence that the devil immune system can be primed to recognise DFTD cells, but additional immune manipulation could be needed for complete protection or induction of tumour regressions.

immunology↗