title: Evaluating vaccinia virus cytokine co-expression in TLR GKO mice.
abstract: Using Toll-like receptor (TLR) and MyD88 gene knock-out (GKO) mice the effect of TLRs and MyD88 on virus replication, interferon (IFN)-β production, natural killer (NK) cell and CD8T cell responses were assessed following ectromelia virus (ECTV) and recombinant vaccinia virus (rVV) infection. The capacity for rVVs encoding cytokines to restore immune function in MyD88(-/-) mice was clearly demonstrated. Results showed that TLR2(-/-), TLR4(-/-)and TLR7(-/-) mice survived ECTV infection whereas MyD88(-/-) and TLR9(-/-)mice, in contrast, were highly susceptible. Next, following infection with rVV, MyD88(-/-) mice elicited reduced serum IFN-β, NK cell and CD8T cell responses compared with wild-type mice, whereas TLR9(-/-) mice showed elevated CD8T cell responses. When MyD88(-/-)mice were infected with rVV co-expressing IFN-β these mice were able to restore IFN-β levels and CD8T cell responses but not NK cell activation. Interestingly, even though rVV co-expressing interleukin (IL)-2 enhanced NK cell activation in MyD88(-/-) mice, this was not associated with an antiviral effect, as observed in normal mice. Surprisingly, co-infection with rVV IL-2/rVV IL-12, but not rVV IL-2/rVV IFN-β, restored the attenuated phenotype of rVV IL-2 in MyD88(-/-) mice indicating that the IL-2/IL-12 combination promotes antiviral responses. Our results clearly show that the CD8T cell defect observed in MyD88(-/-) mice to vaccinia virus infection can be restored by rVV-encoding IFN-β demonstrating the critical role of this cytokine in T cell mediated immunity and illustrates that the model can provide an effective platform for the elucidation of cytokine immunobiology.
authors.affiliation: Emerging Pathogens and Vaccines Program, The John Curtin School of Medical Research, Australian National University, Canberra, Australian Capital Territory, Australia. duncan.sutherland@anu.edu.au
authors.forename: Duncan B
authors.initials: DB
authors.lastname: Sutherland
authors.forename: Charani
authors.initials: C
authors.lastname: Ranasinghe
authors.forename: Matthias
authors.initials: M
authors.lastname: Regner
authors.forename: Simon
authors.initials: S
authors.lastname: Phipps
authors.forename: Klaus I
authors.initials: KI
authors.lastname: Matthaei
authors.forename: Stephanie L
authors.initials: SL
authors.lastname: Day
authors.forename: Ian A
authors.initials: IA
authors.lastname: Ramshaw
mesh_terms: D000818:Animals; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism; D002460:Cell Line; D002522:Chlorocebus aethiops; D016207:Cytokines / Q000235:genetics* / Q000378:metabolism; D004481:Ectromelia virus / Q000502:physiology; D004482:Ectromelia, Infectious / Q000276:immunology / Q000517:prevention & control; D005260:Female; D015967:Gene Expression Regulation, Viral; D005822:Genetic Vectors / Q000235:genetics / Q000378:metabolism; D006801:Humans; D016899:Interferon-beta / Q000235:genetics / Q000378:metabolism; D018664:Interleukin-12 / Q000378:metabolism; D007376:Interleukin-2 / Q000378:metabolism; D007694:Killer Cells, Natural / Q000276:immunology / Q000378:metabolism; D008213:Lymphocyte Activation / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D053594:Myeloid Differentiation Factor 88 / Q000235:genetics*; D010641:Phenotype; D051193:Toll-Like Receptors / Q000235:genetics*; D014616:Vaccinia virus / Q000235:genetics* / Q000378:metabolism*; D014779:Virus Replication / Q000276:immunology
chemical_list: D016207:Cytokines; D007376:Interleukin-2; C507780:Myd88 protein, mouse; D053594:Myeloid Differentiation Factor 88; D051193:Toll-Like Receptors; D018664:Interleukin-12; D016899:Interferon-beta