{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,25]],"date-time":"2026-09-25T18:36:46Z","timestamp":1790361406325,"version":"4.1.0"},"reference-count":31,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2020,5,24]],"date-time":"2020-05-24T00:00:00Z","timestamp":1590278400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Viruses"],"abstract":"<jats:p>Feline infectious peritonitis (FIP) is a viral disease with a high morbidity and mortality by the FIP virus (FIPV, virulent feline coronavirus). Several antiviral drugs for FIP have been identified, but many of these are expensive and not available in veterinary medicine. Hydroxychloroquine (HCQ) is a drug approved by several countries to treat malaria and immune-mediated diseases in humans, and its antiviral effects on other viral infections (e.g., SARS-CoV-2, dengue virus) have been confirmed. We investigated whether HCQ in association with interferon-\u03c9 (IFN-\u03c9) is effective for FIPV in vitro. A total of 100 \u03bcM of HCQ significantly inhibited the replication of types I and II FIPV. Interestingly, the combination of 100 \u03bcM of HCQ and 104 U\/mL of recombinant feline IFN-\u03c9 (rfIFN-\u03c9, veterinary registered drug) increased its antiviral activity against type I FIPV infection. Our study suggested that HCQ and rfIFN-\u03c9 are applicable for treatment of FIP. Further clinical studies are needed to verify the combination of HCQ and rIFN-\u03c9 will be effective and safe treatment for cats with FIP.<\/jats:p>","DOI":"10.3390\/v12050576","type":"journal-article","created":{"date-parts":[[2020,5,25]],"date-time":"2020-05-25T06:43:40Z","timestamp":1590389020000},"page":"576","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":20,"title":["Antiviral Effects of Hydroxychloroquine and Type I Interferon on In Vitro Fatal Feline Coronavirus Infection"],"prefix":"10.3390","volume":"12","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-3468-0708","authenticated-orcid":false,"given":"Tomomi","family":"Takano","sequence":"first","affiliation":[{"name":"Laboratory of Veterinary Infectious Disease, School of Veterinary Medicine, Kitasato University, Towada, Aomori 034-8628, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kumi","family":"Satoh","sequence":"additional","affiliation":[{"name":"Laboratory of Veterinary Infectious Disease, School of Veterinary Medicine, Kitasato University, Towada, Aomori 034-8628, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tomoyoshi","family":"Doki","sequence":"additional","affiliation":[{"name":"Laboratory of Veterinary Infectious Disease, School of Veterinary Medicine, Kitasato University, Towada, Aomori 034-8628, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Taishi","family":"Tanabe","sequence":"additional","affiliation":[{"name":"Laboratory of Veterinary Microbiology, School of Veterinary Medicine, Kitasato University, Towada, Aomori 034-8628, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tsutomu","family":"Hohdatsu","sequence":"additional","affiliation":[{"name":"Laboratory of Veterinary Infectious Disease, School of Veterinary Medicine, Kitasato University, Towada, Aomori 034-8628, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2020,5,24]]},"reference":[{"key":"ref_1","unstructured":"(2020, April 21). 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