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Rift Valley Fever Virus Protein Detected by Multiple Immunohistochemical Methods
Author(s) -
Stietzle Elizabeth,
Gamez M.,
Faburay B.,
Drolet B.S.,
Wilson W.C.,
Richt J.A.,
Davis A.S.
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.925.16
Subject(s) - virology , rift valley fever , immunohistochemistry , biology , arbovirus , reassortment , polyclonal antibodies , antibody , bunyaviridae , virus , phlebovirus , pathology , immunology , medicine , disease , infectious disease (medical specialty) , covid-19
Rift Valley Fever Virus (RVFV), family Bunyaviridae , genus Phlebovirus, is a zoonotic arbovirus endemic to the continent of Africa that spread to the Arabian Peninsula in 2000. RVFV causes abortions and malformed fetuses as well as high mortality in young ruminants including cattle and sheep. In humans, RVFV usually causes an acute febrile illness but can progress to encephalitis, retinitis or hemorrhagic fever. A potential bioweapon, RVFV is classified as a high priority agent by the NIH, CDC and USDA due to a lack of antiviral treatments and approved vaccinations for use outside of endemic countries. This work is part of a larger set of studies focused on developing challenge models in sheep and cattle for testing new vaccines and therapies for RVFV. Here we hypothesized that we could successfully use polyclonal and monoclonal antibodies raised against a variety of RVFV proteins that were previously untested for immunohistochemistry (IHC) to identify viral antigen distribution by bright‐field and fluorescence microscopy in multiple tissues: liver, mesenteric lymph node, spleen, adrenal, kidney and lung. Using formalin‐fixed paraffin‐embedded tissue samples from multiple acute and chronic post‐infection time‐points in both sheep and cattle RVFV studies, we successfully identified viral antigen using multiple IHC detection techniques with antibodies raised against RVFV's nucleoprotein, aminoterminal glycoprotein, and carboxyterminal glycoprotein. An avidin biotin complex technique was determined to be most successful for IHC and a one step indirect technique was used for immunofluorescence. Optimal antibody concentration, chromogen usage and counterstain selection were established for each tissue type and host species. In general, viral antigen was found within lesions already identified by histopathology. Western blots on infected Vero cell lysates were used to confirm antibody specificity. These results provide tools for the aforementioned RVFV studies and a starting point for multi‐label IHC studies focused on questions regarding RVFV pathogenesis including its cell tropism and immunopathology. Support or Funding Information State of Kansas National Bio and Agro‐Defense Facility Transition Funding and the Department of Homeland Security Grant Award Number DHS‐2010‐ST‐061‐AG0001(A) H&E RVFV infected sheep liver, (B) polyclonal anti‐RVFV N (brown) in same liver section, bar 100 μm; (C) monoclonal anti‐RVFV N (star), hemosiderin (arrow) in infected lymph node, bar 50 μm; (D–F) sheep liver DAPI (blue), monoclonal anti‐RVFV Gn (red), merge bar 30 μm.