title: CCR5 ameliorates Japanese encephalitis via dictating the equilibrium of regulatory CD4(+)Foxp3(+) T and IL-17(+)CD4(+) Th17 cells.
abstract: CCR5 is a CC chemokine receptor involved in the migration of effector leukocytes including macrophages, NK, and T cells into inflamed tissues. Also, the role of CCR5 in CD4(+)Foxp3(+) regulatory T cell (Treg) homing has recently begun to grab attention. Japanese encephalitis (JE) is defined as severe neuroinflammation of the central nervous system (CNS) following infection with mosquito-borne flavivirus JE virus. However, the potential contribution of CCR5 to JE progression via mediating CD4(+)Foxp3(+) Treg homing has not been investigated.
  
  
  
  Infected wild-type (Ccr5(+/+)) and CCR5-deficient (Ccr5(-/-)) mice were examined daily for mortality and clinical signs, and neuroinflammation in the CNS was evaluated by infiltration of inflammatory leukocytes and cytokine expression. In addition, viral burden, NK- and JEV-specific T cell responses were analyzed. Adoptive transfer of CCR5(+)CD4(+)Foxp3(+) Tregs was used to evaluate the role of Tregs in JE progression.
  
  
  
  CCR5 ablation exacerbated JE without altering viral burden in the extraneural and CNS tissues, as manifested by increased CNS infiltration of Ly-6C(hi) monocytes and Ly-6G(hi) granulocytes. Compared to Ccr5(+/+) mice, Ccr5(-/-) mice unexpectedly showed increased responses of IFN-γ(+)NK and CD8(+) T cells in the spleen, but not CD4(+) T cells. More interestingly, CCR5-ablation resulted in a skewed response to IL-17(+)CD4(+) Th17 cells and correspondingly reduced CD4(+)Foxp3(+) Tregs in the spleen and brain, which was closely associated with exacerbated JE. Our results also revealed that adoptive transfer of sorted CCR5(+)CD4(+)Foxp3(+) Tregs into Ccr5(-/-) mice could ameliorate JE progression without apparently altering the viral burden and CNS infiltration of IL-17(+)CD4(+) Th17 cells, myeloid-derived Ly-6C(hi) monocytes and Ly-6G(hi) granulocytes. Instead, adoptive transfer of CCR5(+)CD4(+)Foxp3(+) Tregs into Ccr5(-/-) mice resulted in increased expression of anti-inflammatory cytokines (IL-10 and TGF-β) in the spleen and brain, and transferred CCR5(+) Tregs were found to produce IL-10.
  
  
  
  CCR5 regulates JE progression via governing timely and appropriate CNS infiltration of CD4(+)Foxp3(+) Tregs, thereby facilitating host survival. Therefore, this critical and extended role of CCR5 in JE raises possible safety concerns regarding the use of CCR5 antagonists in human immunodeficiency virus (HIV)-infected individuals who inhabit regions in which both HIV and flaviviruses, such as JEV and West Nile virus, are endemic.
authors.affiliation: College of Veterinary Medicine and Bio-Safety Research Institute, Chonbuk National University, Iksan, 54596, Republic of Korea.
authors.forename: Jin Hyoung
authors.initials: JH
authors.lastname: Kim
authors.affiliation: College of Veterinary Medicine and Bio-Safety Research Institute, Chonbuk National University, Iksan, 54596, Republic of Korea.
authors.forename: Ajit Mahadev
authors.initials: AM
authors.lastname: Patil
authors.affiliation: College of Veterinary Medicine and Bio-Safety Research Institute, Chonbuk National University, Iksan, 54596, Republic of Korea.
authors.forename: Jin Young
authors.initials: JY
authors.lastname: Choi
authors.affiliation: College of Veterinary Medicine and Bio-Safety Research Institute, Chonbuk National University, Iksan, 54596, Republic of Korea.
authors.forename: Seong Bum
authors.initials: SB
authors.lastname: Kim
authors.affiliation: College of Veterinary Medicine and Bio-Safety Research Institute, Chonbuk National University, Iksan, 54596, Republic of Korea.
authors.forename: Erdenebelig
authors.initials: E
authors.lastname: Uyangaa
authors.affiliation: College of Veterinary Medicine and Bio-Safety Research Institute, Chonbuk National University, Iksan, 54596, Republic of Korea.
authors.forename: Ferdaus Mohd Altaf
authors.initials: FM
authors.lastname: Hossain
authors.affiliation: College of Veterinary Medicine and Bio-Safety Research Institute, Chonbuk National University, Iksan, 54596, Republic of Korea.|Department of Bioactive Material Sciences, Graduate School, Chonbuk National University, Jeonju, 54896, Republic of Korea.
authors.forename: Sang-Youel
authors.initials: SY
authors.lastname: Park
authors.affiliation: College of Veterinary Medicine and Bio-Safety Research Institute, Chonbuk National University, Iksan, 54596, Republic of Korea.|Department of Bioactive Material Sciences, Graduate School, Chonbuk National University, Jeonju, 54896, Republic of Korea.
authors.forename: John Hwa
authors.initials: JH
authors.lastname: Lee
authors.affiliation: College of Veterinary Medicine and Bio-Safety Research Institute, Chonbuk National University, Iksan, 54596, Republic of Korea. vetvirus@chonbuk.ac.kr.|Department of Bioactive Material Sciences, Graduate School, Chonbuk National University, Jeonju, 54896, Republic of Korea. vetvirus@chonbuk.ac.kr.
authors.forename: Seong Kug
authors.initials: SK
authors.lastname: Eo
mesh_terms: D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000378:metabolism*; D002465:Cell Movement / Q000502:physiology; D002490:Central Nervous System / Q000378:metabolism* / Q000473:pathology / Q000821:virology; D016207:Cytokines / Q000235:genetics / Q000378:metabolism; D004195:Disease Models, Animal; D018450:Disease Progression; D004672:Encephalitis, Japanese / Q000235:genetics / Q000473:pathology*; D005260:Female; D051858:Forkhead Transcription Factors / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000502:physiology; D020381:Interleukin-17 / Q000235:genetics / Q000378:metabolism*; D007694:Killer Cells, Natural / Q000378:metabolism / Q000473:pathology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D022423:Myeloid Cells / Q000378:metabolism / Q000473:pathology / Q000821:virology; D019713:Receptors, CCR5 / Q000235:genetics / Q000378:metabolism*; D013154:Spleen / Q000378:metabolism / Q000473:pathology / Q000821:virology; D058504:Th17 Cells / Q000378:metabolism*; D014779:Virus Replication / Q000235:genetics
chemical_list: C000592874:CCR5 protein, mouse; D016207:Cytokines; D051858:Forkhead Transcription Factors; C498833:Foxp3 protein, mouse; D020381:Interleukin-17; D019713:Receptors, CCR5
keywords: CCR5; CD4+Foxp3+ Tregs; IL-17+CD4+ Th17; Japanese encephalitis; Neuroinflammation