Middle East respiratory coronavirus (MERS-CoV) internalized by llama alveolar macrophages does not result in virus replication or induction of pro-inflammatory cytokines

Severe Middle East respiratory syndrome (MERS) is characterized by massive infiltration of immune cells in lungs. MERS-coronavirus (MERS-CoV) replicates in vitro in human macrophages, inducing high proinflammatory responses. In contrast, camelids, the main reservoir for MERS-CoV, are asymptomatic carriers. Although limited infiltration of leukocytes has been observed in the lower respiratory tract of camelids, their role during infection remains unknown. Here we studied whether llama alveolar macrophages (LAMs) are susceptible to MERS-CoV infection and can elicit pro-inflammatory responses. MERS-CoV did not replicate in LAMs; however, they effectively capture and degrade viral particles. Moreover, transcriptomic analyses showed that LAMs do not induce pro-inflammatory cytokines upon MERS-CoV sensing. ; This study was performed as part of the Zoonotic Anticipation and Preparedness Initiative (ZAPI project) [Innovative Medicines initiative (IMI) grant 115760] and the VetBioNet project (EU Grant Agreement INFRA-2016-1 Nº731014), with assistance and financial support from IMI and the European Commission and contributions from EFPIA partners and from grant RTI2018-09445-B-100 from the Ministry of Science and Innovation of Spain (to C.R.). J.R. was partially supported by the VetBioNet project. IRTA is supported by CERCA Programme/Generalitat de Catalunya. ; info:eu-repo/semantics/publishedVersion