TY - JOUR
T1 - Seoul virus enhances regulatory and reduces proinflammatory responses in male Norway rats
AU - Easterbrook, Judith D.
AU - Klein, Sabra L.
PY - 2008/7
Y1 - 2008/7
N2 - Zoonotic pathogens, including hantaviruses, are maintained in the environment by causing persistent infection in the absence of disease in their reservoir hosts. Spillover of hantaviruses to humans can cause severe disease that is mediated by excessive proinflammatory responses. The mechanisms mediating hantaviral persistence in rodent reservoirs remain largely unknown. Male Norway rats were inoculated with their species-specific hantavirus, Seoul virus (SEOV), and viral RNA, cytokine, and chemokine responses were evaluated in spleen and lung tissue. More viral RNA was detectable in the lungs than spleen, with copies of SEOV peaking 15-30 days post-inoculation (p.i.) and persisting for 60 days p.i. In the lungs, the expression and production of proinflammatory mediators (i.e., IL-1β, IL-6, TNF-α, IFN-γ, CCL5, CCL2, CX3CL1, CXCL10, VCAM, VEGF, and NOS2) remained at or below baseline throughout SEOV infection; whereas, regulatory factors, including TGF-β and FoxP3 were elevated. Conversely, in the spleen, proinflammatory responses were induced while regulatory responses remained unchanged during infection. To determine whether reduced proinflammatory responses mediate hantavirus persistence in the lungs, male rats were administered rIL-1β or vehicle for 30 days during SEOV infection. SEOV persistence and shedding were not affected by IL-1β treatment. Proinflammatory responses were elevated in rIL-1β-treated rats, but remained within physiological levels, suggesting that supra-physiological concentrations may be necessary for viral clearance at the cost of causing disease. Elevated regulatory responses may suppress excessively high proinflammatory responses at a site of elevated SEOV replication to contribute to viral persistence and prevent proinflammatory-mediated disease in reservoir hosts.
AB - Zoonotic pathogens, including hantaviruses, are maintained in the environment by causing persistent infection in the absence of disease in their reservoir hosts. Spillover of hantaviruses to humans can cause severe disease that is mediated by excessive proinflammatory responses. The mechanisms mediating hantaviral persistence in rodent reservoirs remain largely unknown. Male Norway rats were inoculated with their species-specific hantavirus, Seoul virus (SEOV), and viral RNA, cytokine, and chemokine responses were evaluated in spleen and lung tissue. More viral RNA was detectable in the lungs than spleen, with copies of SEOV peaking 15-30 days post-inoculation (p.i.) and persisting for 60 days p.i. In the lungs, the expression and production of proinflammatory mediators (i.e., IL-1β, IL-6, TNF-α, IFN-γ, CCL5, CCL2, CX3CL1, CXCL10, VCAM, VEGF, and NOS2) remained at or below baseline throughout SEOV infection; whereas, regulatory factors, including TGF-β and FoxP3 were elevated. Conversely, in the spleen, proinflammatory responses were induced while regulatory responses remained unchanged during infection. To determine whether reduced proinflammatory responses mediate hantavirus persistence in the lungs, male rats were administered rIL-1β or vehicle for 30 days during SEOV infection. SEOV persistence and shedding were not affected by IL-1β treatment. Proinflammatory responses were elevated in rIL-1β-treated rats, but remained within physiological levels, suggesting that supra-physiological concentrations may be necessary for viral clearance at the cost of causing disease. Elevated regulatory responses may suppress excessively high proinflammatory responses at a site of elevated SEOV replication to contribute to viral persistence and prevent proinflammatory-mediated disease in reservoir hosts.
KW - HFRS
KW - IL-1β
KW - Regulatory T cell
KW - TGF-β
KW - TNF
KW - Zoonotic
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U2 - 10.1002/jmv.21213
DO - 10.1002/jmv.21213
M3 - Article
C2 - 18461618
AN - SCOPUS:43949124481
SN - 0146-6615
VL - 80
SP - 1308
EP - 1318
JO - Journal of Medical Virology
JF - Journal of Medical Virology
IS - 7
ER -