A human in vitro model system for investigating genome-wide host responses to SARS coronavirus infection.
BACKGROUND
The molecular basis of severe acute respiratory syndrome (SARS) coronavirus (CoV) induced pathology is still largely unclear. Many SARS patients suffer respiratory distress brought on by interstitial infiltration and frequently show peripheral blood lymphopenia and occasional leucopenia. One possible cause of this could be interstitial inflammation, following a localized host response. In this study, we therefore examine the immune response of SARS-CoV in human peripheral blood mononuclear cells (PBMCs) over the first 24 hours.


METHODS
PBMCs from normal healthy donors were inoculated in vitro with SARS-CoV and the viral replication kinetics was studied by real-time quantitative assays. SARS-CoV specific gene expression changes were examined by high-density oligonucleotide array analysis.


RESULTS
We observed that SARS-CoV was capable of infecting and replicating in PBMCs and the kinetics of viral replication was variable among the donors. SARS-CoV antibody binding assays indicated that SARS specific antibodies inhibited SARS-CoV viral replication. Array data showed monocyte-macrophage cell activation, coagulation pathway upregulation and cytokine production together with lung trafficking chemokines such as IL8 and IL17, possibly activated through the TLR9 signaling pathway; that mimicked clinical features of the disease.


CONCLUSIONS
The identification of human blood mononuclear cells as a direct target of SARS-CoV in the model system described here provides a new insight into disease pathology and a tool for investigating the host response and mechanisms of pathogenesis.
Ng
Lisa F P
LF
Genome Institute of Singapore, 60 Biopolis Street, Genome, #02-01, Singapore 138672. ngfp@gis.a-star.edu.sg
Hibberd
Martin L
ML
Ooi
Eng-Eong
EE
Tang
Kin-Fai
KF
Neo
Soek-Ying
SY
Tan
Jenny
J
Murthy
Karuturi R Krishna
KR
Vega
Vinsensius B
VB
Chia
Jer-Ming
JM
Liu
Edison T
ET
Ren
Ee-Chee
EC
D000818:Animals; D002522:Chlorocebus aethiops; D015967:Gene Expression Regulation, Viral; D006801:Humans; D007700:Kinetics; D007963:Leukocytes, Mononuclear / Q000821:virology*; D020411:Oligonucleotide Array Sequence Analysis; D016133:Polymerase Chain Reaction; D012367:RNA, Viral / Q000235:genetics / Q000302:isolation & purification; D045473:Severe acute respiratory syndrome-related coronavirus / Q000235:genetics / Q000276:immunology / Q000502:physiology*; D045169:Severe Acute Respiratory Syndrome / Q000276:immunology / Q000821:virology*; D014709:Vero Cells; D014779:Virus Replication / Q000502:physiology*
D012367:RNA, Viral