Pathogenesis of Ebola hemorrhagic fever in cynomolgus macaques: evidence that dendritic cells are early and sustained targets of infection.
Ebola virus (EBOV) infection causes a severe and fatal hemorrhagic disease that in many ways appears to be similar in humans and nonhuman primates; however, little is known about the development of EBOV hemorrhagic fever. In the present study, 21 cynomolgus monkeys were experimentally infected with EBOV and examined sequentially over a 6-day period to investigate the pathological events of EBOV infection that lead to death. Importantly, dendritic cells in lymphoid tissues were identified as early and sustained targets of EBOV, implicating their important role in the immunosuppression characteristic of EBOV infections. Bystander lymphocyte apoptosis, previously described in end-stage tissues, occurred early in the disease-course in intravascular and extravascular locations. Of note, apoptosis and loss of NK cells was a prominent finding, suggesting the importance of innate immunity in determining the fate of the host. Analysis of peripheral blood mononuclear cell gene expression showed temporal increases in tumor necrosis factor-related apoptosis-inducing ligand and Fas transcripts, revealing a possible mechanism for the observed bystander apoptosis, while up-regulation of NAIP and cIAP2 mRNA suggest that EBOV has evolved additional mechanisms to resist host defenses by inducing protective transcripts in cells that it infects. The sequence of pathogenetic events identified in this study should provide new targets for rational prophylactic and chemotherapeutic interventions.
Geisbert
Thomas W
TW
United States Army Medical Institute of Infectious Diseases, Fort Detrick, MD 21702-5011, USA. tom.geisbert@amedd.army.mil
Hensley
Lisa E
LE
Larsen
Tom
T
Young
Howard A
HA
Reed
Douglas S
DS
Geisbert
Joan B
JB
Scott
Dana P
DP
Kagan
Elliott
E
Jahrling
Peter B
PB
Davis
Kelly J
KJ
D000818:Animals; D018925:Chemokines / Q000097:blood; D016638:Critical Illness; D016207:Cytokines / Q000097:blood; D003713:Dendritic Cells / Q000821:virology*; D004731:Endotoxins / Q000097:blood; D005434:Flow Cytometry; D019142:Hemorrhagic Fever, Ebola / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology / Q000821:virology*; D007958:Leukocyte Count; D008137:Longitudinal Studies; D008252:Macaca fascicularis; D008297:Male; D009566:Nitrates / Q000097:blood; D013997:Time Factors; D019562:Viral Load; D014766:Viremia / Q000821:virology
D018925:Chemokines; D016207:Cytokines; D004731:Endotoxins; D009566:Nitrates