SARS-CoV-2 Accessory Protein ORF8 Decreases Antibody-Dependent Cellular Cytotoxicity

Viruses

Andrés Finzi¹  Halima Medjahed¹  Guillaume Beaudoin-Bussières¹  Gabrielle Gendron-Lepage¹  Jonathan Richard¹  Catherine Bourassa¹  Zhen Wang²  Ariana Arduini²  Qinghua Pan²  Chen Liang² 

[1] Centre de Recherche du CHUM, Montreal, QC H2X 0A9, Canada;Lady Davis Institute, Jewish General Hospital, Montreal, QC H3T 1E2, Canada;

关键词: coronavirus;    SARS-CoV-2;    ORF8;    accessory protein;    Fc-mediated effector function;    ADCC;   

DOI  :  10.3390/v14061237

来源: DOAJ

【 摘 要 】

Viruses use many different strategies to evade host immune responses. In the case of SARS-CoV-2, its Spike mutates rapidly to escape from neutralizing antibodies. In addition to this strategy, ORF8, a small accessory protein encoded by SARS-CoV-2, helps immune evasion by reducing the susceptibility of SARS-CoV-2-infected cells to the cytotoxic CD8+ T cell response. Interestingly, among all accessory proteins, ORF8 is rapidly evolving and a deletion in this protein has been linked to milder disease. Here, we studied the effect of ORF8 on peripheral blood mononuclear cells (PBMC). Specifically, we found that ORF8 can bind monocytes as well as NK cells. Strikingly, ORF8 binds CD16a (FcγRIIIA) with nanomolar affinity and decreases the overall level of CD16 at the surface of monocytes and, to a lesser extent, NK cells. This decrease significantly reduces the capacity of PBMCs and particularly monocytes to mediate antibody-dependent cellular cytotoxicity (ADCC). Overall, our data identifies a new immune-evasion activity used by SARS-CoV-2 to escape humoral responses.

【 授权许可】

Unknown