{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,17]],"date-time":"2026-10-17T15:00:04Z","timestamp":1792249204854,"version":"4.4.0"},"reference-count":34,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2022,8,14]],"date-time":"2022-08-14T00:00:00Z","timestamp":1660435200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Ministry of Education, Culture, Sports, Science and Technology"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Pathogens"],"abstract":"<jats:p>Koala retrovirus (KoRV) exists in both endogenous and exogenous forms and has appeared as a major threat to koala health and conservation. Currently, there are twelve identified KoRV subtypes: an endogenous subtype (KoRV-A) and eleven exogenous subtypes (KoRV-B to -I, KoRV-K, -L, and -M). However, information about subtype-related immune responses in koalas against multiple KoRV infections is limited. In this study, we investigated KoRV-subtype (A, B, C, D, and F)-related immunophenotypic changes, including CD4, CD8b, IFN-\u03b3, IL-6, and IL-10 mRNA expression, in peripheral blood mononuclear cells (PBMCs) obtained from captive koalas (n = 37) infected with multiple KoRV subtypes (KoRV-A to F) reared in seven Japanese zoos. Based on KoRV subtype infection profiles, no significant difference in CD4 and CD8b mRNA expression was observed in the study populations. Based on the different KoRV subtype infections, we found that the IFN-\u03b3 mRNA expression in koala PMBCs differs insignificantly (p = 0.0534). In addition, IL-6 and IL-10 mRNA expression also did not vary significantly in koala PBMCs based on KoRV subtype differences. We also investigated the Toll-like receptors (TLRs) response, including TLR2\u201310, and TLR13 mRNA in koala PBMCs infected with multiple KoRV subtypes. Significant differential expression of TLR5, 7, 9, 10, and 13 mRNA was observed in the PBMCs from koalas infected with different KoRV subtypes. Therefore, based on the findings of this study, it is assumed that co-infection of multiple KoRV subtypes might modify the host innate immune response, including IFN-\u03b3 and TLRs responses. However, to have a more clear understanding regarding the effect of multiple KoRV subtypes on host cytokines and TLR response and pathogenesis, further large-scale studies including the koalas negative for KoRV and koalas infected with other KoRV subtypes (KoRV-A to -I, KoRV-K, -L and -M) are required.<\/jats:p>","DOI":"10.3390\/pathogens11080911","type":"journal-article","created":{"date-parts":[[2022,8,15]],"date-time":"2022-08-15T03:33:20Z","timestamp":1660534400000},"page":"911","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Molecular Insights into Innate Immune Response in Captive Koala Peripheral Blood Mononuclear Cells Co-Infected with Multiple Koala Retrovirus Subtypes"],"prefix":"10.3390","volume":"11","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-4806-9843","authenticated-orcid":false,"given":"Mohammad Enamul Hoque","family":"Kayesh","sequence":"first","affiliation":[{"name":"Transboundary Animal Diseases Centre, Joint Faculty of Veterinary Medicine, Kagoshima University, Kagoshima 890-0065, Japan"},{"name":"Department of Microbiology and Public Health, Faculty of Animal Science and Veterinary Medicine, Patuakhali Science and Technology University, Barishal 8210, Bangladesh"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6224-2986","authenticated-orcid":false,"given":"Md Abul","family":"Hashem","sequence":"additional","affiliation":[{"name":"Transboundary Animal Diseases Centre, Joint Faculty of Veterinary Medicine, Kagoshima University, Kagoshima 890-0065, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Fumie","family":"Maetani","sequence":"additional","affiliation":[{"name":"Hirakawa Zoological Park, Kagoshima 891-0133, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Atsushi","family":"Goto","sequence":"additional","affiliation":[{"name":"Awaji Farm Park England Hill Zoo, Minamiawaji 665-0443, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Noriko","family":"Nagata","sequence":"additional","affiliation":[{"name":"Tama Zoological Park, Tokyo 191-0041, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Aki","family":"Kasori","sequence":"additional","affiliation":[{"name":"Kanazawa Zoo, Yokohama 236-0042, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tetsuya","family":"Imanishi","sequence":"additional","affiliation":[{"name":"Nagoya Higashiyama Zoo, Nagoya 464-0804, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4403-2018","authenticated-orcid":false,"given":"Kyoko","family":"Tsukiyama-Kohara","sequence":"additional","affiliation":[{"name":"Transboundary Animal Diseases Centre, Joint Faculty of Veterinary Medicine, Kagoshima University, Kagoshima 890-0065, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2022,8,14]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"4264","DOI":"10.1128\/JVI.74.9.4264-4272.2000","article-title":"The nucleotide sequence of koala (Phascolarctos cinereus) retrovirus: A novel type C endogenous virus related to Gibbon ape leukemia virus","volume":"74","author":"Hanger","year":"2000","journal-title":"J. Virol."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"783","DOI":"10.1099\/vir.0.80547-0","article-title":"Real-time reverse transcriptase PCR for the endogenous koala retrovirus reveals an association between plasma viral load and neoplastic disease in koalas","volume":"86","author":"Tarlinton","year":"2005","journal-title":"J. Gen. Virol."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"79","DOI":"10.1038\/nature04841","article-title":"Retroviral invasion of the koala genome","volume":"442","author":"Tarlinton","year":"2006","journal-title":"Nature"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"583","DOI":"10.1093\/femsre\/fuaa024","article-title":"Helping koalas battle disease\u2014Recent advances in Chlamydia and koala retrovirus (KoRV) disease understanding and treatment in koalas","volume":"44","author":"Quigley","year":"2020","journal-title":"FEMS Microbiol. Rev."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"619","DOI":"10.1046\/j.1523-1739.2000.99383.x","article-title":"Overview, critical assessment, and conservation implications of koala distribution and abundance","volume":"14","author":"Melzer","year":"2000","journal-title":"Conserv. Biol."},{"key":"ref_6","unstructured":"Woinarski, J., and Burbidge, A.A. (2021, September 30). Phascolarctos Cinereus (Amended Version of 2016 Assessment). The IUCN Red List of Threatened Species 2020: E.T16892A166496779. Available online: https:\/\/www.iucnredlist.org\/species\/16892\/166496779."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"2409","DOI":"10.1007\/s00705-020-04770-9","article-title":"Koala retrovirus epidemiology, transmission mode, pathogenesis, and host immune response in koalas (Phascolarctos cinereus): A review","volume":"165","author":"Kayesh","year":"2020","journal-title":"Arch. Virol."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"11547","DOI":"10.1073\/pnas.1304704110","article-title":"An exogenous retrovirus isolated from koalas with malignant neoplasias in a US zoo","volume":"110","author":"Xu","year":"2013","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"e00019-20","DOI":"10.1128\/JVI.00019-20","article-title":"Transmission of Koala Retrovirus from Parent Koalas to a Joey in a Japanese Zoo","volume":"94","author":"Hashem","year":"2020","journal-title":"J. Virol."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"52","DOI":"10.3390\/cimb43010005","article-title":"Toll-Like Receptor and Cytokine Responses to Infection with Endogenous and Exogenous Koala Retrovirus, and Vaccination as a Control Strategy","volume":"43","author":"Kayesh","year":"2021","journal-title":"Curr. Issues Mol. Biol."},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Blyton, M.D.J., Pyne, M., Young, P., and Chappell, K. (2022). Koala retrovirus load and non-A subtypes are associated with secondary disease among wild northern koalas. PLoS Pathog., 18.","DOI":"10.1371\/journal.ppat.1010513"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"e2024021118","DOI":"10.1073\/pnas.2024021118","article-title":"Koala retrovirus genetic diversity and transmission dynamics within captive koala populations","volume":"118","author":"Joyce","year":"2021","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"15838","DOI":"10.1038\/s41598-017-16171-1","article-title":"Long-read genome sequence assembly provides insight into ongoing retroviral invasion of the koala germline","volume":"7","author":"Hobbs","year":"2017","journal-title":"Sci. Rep."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"8609","DOI":"10.1073\/pnas.1807598115","article-title":"Degradation and remobilization of endogenous retroviruses by recombination during the earliest stages of a germ-line invasion","volume":"115","author":"Lober","year":"2018","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"1102","DOI":"10.1038\/s41588-018-0153-5","article-title":"Adaptation and conservation insights from the koala genome","volume":"50","author":"Johnson","year":"2018","journal-title":"Nat. Genet."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"225","DOI":"10.1146\/annurev-animal-050620-101416","article-title":"Endogenous Retroviruses Drive Resistance and Promotion of Exogenous Retroviral Homologs","volume":"9","author":"Chiu","year":"2021","journal-title":"Annu. Rev. Anim. Biosci."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"241","DOI":"10.1186\/gb-2006-7-11-241","article-title":"Koala retrovirus: A genome invasion in real time","volume":"7","author":"Stoye","year":"2006","journal-title":"Genome Biol."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"3413","DOI":"10.1007\/s00018-008-8499-y","article-title":"Biology and evolution of the endogenous koala retrovirus","volume":"65","author":"Tarlinton","year":"2008","journal-title":"Cell Mol. Life Sci."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"108","DOI":"10.1186\/1742-4690-10-108","article-title":"Koala retroviruses: Characterization and impact on the life of koalas","volume":"10","author":"Denner","year":"2013","journal-title":"Retrovirology"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"4537","DOI":"10.1007\/s00018-013-1393-2","article-title":"Transcriptional control of CD4 and CD8 coreceptor expression during T cell development","volume":"70","author":"Ellmeier","year":"2013","journal-title":"Cell Mol. Life Sci."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"791","DOI":"10.1038\/ni1095","article-title":"CD4 enhances T cell sensitivity to antigen by coordinating Lck accumulation at the immunological synapse","volume":"5","author":"Li","year":"2004","journal-title":"Nat. Immunol."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"11455","DOI":"10.1158\/0008-5472.CAN-06-2379","article-title":"Influence of human CD8 on antigen recognition by T-cell receptor-transduced cells","volume":"66","author":"Lyons","year":"2006","journal-title":"Cancer Res."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"1161","DOI":"10.1016\/j.jmb.2013.12.003","article-title":"Innate antiviral immune signaling, viral evasion and modulation by HIV-1","volume":"426","author":"Rustagi","year":"2014","journal-title":"J. Mol. Biol."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"573","DOI":"10.1146\/annurev-virology-100114-055226","article-title":"Innate and Adaptive Immune Regulation during Chronic Viral Infections","volume":"2","author":"Zuniga","year":"2015","journal-title":"Annu. Rev. Virol."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"1044","DOI":"10.1016\/j.cell.2020.02.041","article-title":"Toll-like Receptors and the Control of Immunity","volume":"180","author":"Fitzgerald","year":"2020","journal-title":"Cell"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"637","DOI":"10.1016\/j.immuni.2011.05.006","article-title":"Toll-like receptors and their crosstalk with other innate receptors in infection and immunity","volume":"34","author":"Kawai","year":"2011","journal-title":"Immunity"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"805","DOI":"10.1016\/j.cell.2010.01.022","article-title":"Pattern recognition receptors and inflammation","volume":"140","author":"Takeuchi","year":"2010","journal-title":"Cell"},{"key":"ref_28","doi-asserted-by":"crossref","unstructured":"Cui, J., Frankham, G.J., Johnson, R.N., Polkinghorne, A., Timms, P., O\u2019Meally, D., Cheng, Y., and Belov, K. (2015). SNP marker discovery in koala TLR genes. PLoS ONE, 10.","DOI":"10.1371\/journal.pone.0121068"},{"key":"ref_29","doi-asserted-by":"crossref","unstructured":"Kayesh, M.E.H., Hashem, M.A., Maetani, F., Eiei, T., Mochizuki, K., Ochiai, S., Ito, A., Ito, N., Sakurai, H., and Asai, T. (2020). CD4, CD8b, and Cytokines Expression Profiles in Peripheral Blood Mononuclear Cells Infected with Different Subtypes of KoRV from Koalas (Phascolarctos cinereus) in a Japanese Zoo. Viruses, 12.","DOI":"10.3390\/v12121415"},{"key":"ref_30","doi-asserted-by":"crossref","unstructured":"Kayesh, M.E.H., Hashem, M.A., and Tsukiyama-Kohara, K. (2021). Toll-Like Receptor Expression Profiles in Koala (Phascolarctos cinereus) Peripheral Blood Mononuclear Cells Infected with Multiple KoRV Subtypes. Animals, 11.","DOI":"10.3390\/ani11040983"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"105297","DOI":"10.1016\/j.meegid.2022.105297","article-title":"Subtype distribution and expression of the koala retrovirus in the Japanese zoo koala population","volume":"102","author":"Hashem","year":"2022","journal-title":"Infect Genet. Evol."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"65","DOI":"10.1292\/jvms.10-0250","article-title":"Isolation of koala retroviruses from koalas in Japan","volume":"73","author":"Miyazawa","year":"2011","journal-title":"J. Vet. Med. Sci."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"757","DOI":"10.1007\/s00705-019-04149-5","article-title":"Molecular dynamics of koala retrovirus infection in captive koalas in Japan","volume":"164","author":"Kayesh","year":"2019","journal-title":"Arch. Virol."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"e280","DOI":"10.7717\/peerj.280","article-title":"Expression profiles of the immune genes CD4, CD8beta, IFNgamma, IL-4, IL-6 and IL-10 in mitogen-stimulated koala lymphocytes (Phascolarctos cinereus) by qRT-PCR","volume":"2","author":"Maher","year":"2014","journal-title":"PeerJ"}],"container-title":["Pathogens"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2076-0817\/11\/8\/911\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T00:08:32Z","timestamp":1760141312000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2076-0817\/11\/8\/911"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,8,14]]},"references-count":34,"journal-issue":{"issue":"8","published-online":{"date-parts":[[2022,8]]}},"alternative-id":["pathogens11080911"],"URL":"https:\/\/doi.org\/10.3390\/pathogens11080911","relation":{},"ISSN":["2076-0817"],"issn-type":[{"value":"2076-0817","type":"electronic"}],"subject":[],"published":{"date-parts":[[2022,8,14]]}}}