title: Characterisation of a K390R ITK kinase dead transgenic mouse--implications for ITK as a therapeutic target.
abstract: Interleukin-2 inducible tyrosine kinase (ITK) is expressed in T cells and plays a critical role in signalling through the T cell receptor. Evidence, mainly from knockout mice, has suggested that ITK plays a particularly important function in Th2 cells and this has prompted significant efforts to discover ITK inhibitors for the treatment of allergic disease. However, ITK is known to have functions outside of its kinase domain and in general kinase knockouts are often not good models for the behaviour of small molecule inhibitors. Consequently we have developed a transgenic mouse where the wild type Itk allele has been replaced by a kinase dead Itk allele containing an inactivating K390R point mutation (Itk-KD mice). We have characterised the immune phenotype of these naive mice and their responses to airway inflammation. Unlike Itk knockout (Itk-/-) mice, T-cells from Itk-KD mice can polymerise actin in response to CD3 activation. The lymph nodes from Itk-KD mice showed more prominent germinal centres than wild type mice and serum antibody levels were significantly abnormal. Unlike the Itk-/-, γδ T cells in the spleens of the Itk-KD mice had an impaired ability to secrete Th2 cytokines in response to anti-CD3 stimulation whilst the expression of ICOS was not significantly different to wild type. However ICOS expression is markedly increased on αβCD3+ cells from the spleens of naïve Itk-KD compared to WT mice. The Itk-KD mice were largely protected from inflammatory symptoms in an Ovalbumin model of airway inflammation. Consequently, our studies have revealed many similarities but some differences between Itk-/-and Itk-KD transgenic mice. The abnormal antibody response and enhanced ICOS expression on CD3+ cells has implications for the consideration of ITK as a therapeutic target.
authors.affiliation: Respiratory Therapy Area, GlaxoSmithKline, Stevenage, Herts, United Kingdom.
authors.forename: Angela
authors.initials: A
authors.lastname: Deakin
authors.affiliation: Laboratory Animal Sciences, GlaxoSmithKline, Stevenage, Herts, United Kingdom.
authors.forename: Graham
authors.initials: G
authors.lastname: Duddy
authors.affiliation: Laboratory Animal Sciences, GlaxoSmithKline, Stevenage, Herts, United Kingdom.
authors.forename: Steve
authors.initials: S
authors.lastname: Wilson
authors.affiliation: Laboratory Animal Sciences, GlaxoSmithKline, Stevenage, Herts, United Kingdom.
authors.forename: Steve
authors.initials: S
authors.lastname: Harrison
authors.affiliation: Laboratory Animal Sciences, GlaxoSmithKline, Stevenage, Herts, United Kingdom.
authors.forename: Judi
authors.initials: J
authors.lastname: Latcham
authors.affiliation: Laboratory Animal Sciences, GlaxoSmithKline, Stevenage, Herts, United Kingdom.
authors.forename: Mick
authors.initials: M
authors.lastname: Fulleylove
authors.affiliation: Laboratory Animal Sciences, GlaxoSmithKline, Stevenage, Herts, United Kingdom.
authors.forename: Sylvia
authors.initials: S
authors.lastname: Fung
authors.affiliation: Laboratory Animal Sciences, GlaxoSmithKline, Stevenage, Herts, United Kingdom.
authors.forename: Jason
authors.initials: J
authors.lastname: Smith
authors.affiliation: Platform Technology and Sciences, GlaxoSmithKline, Stevenage, Herts, United Kingdom.
authors.forename: Mike
authors.initials: M
authors.lastname: Pedrick
authors.affiliation: Platform Technology and Sciences, GlaxoSmithKline, Stevenage, Herts, United Kingdom.
authors.forename: Tom
authors.initials: T
authors.lastname: McKevitt
authors.affiliation: Respiratory Therapy Area, GlaxoSmithKline, Stevenage, Herts, United Kingdom.
authors.forename: Leigh
authors.initials: L
authors.lastname: Felton
authors.affiliation: Respiratory Therapy Area, GlaxoSmithKline, Stevenage, Herts, United Kingdom.
authors.forename: Joanne
authors.initials: J
authors.lastname: Morley
authors.affiliation: Respiratory Therapy Area, GlaxoSmithKline, Stevenage, Herts, United Kingdom.
authors.forename: Diana
authors.initials: D
authors.lastname: Quint
authors.affiliation: Respiratory Therapy Area, GlaxoSmithKline, Stevenage, Herts, United Kingdom.
authors.forename: Dilniya
authors.initials: D
authors.lastname: Fattah
authors.affiliation: Respiratory Therapy Area, GlaxoSmithKline, Stevenage, Herts, United Kingdom.
authors.forename: Brian
authors.initials: B
authors.lastname: Hayes
authors.affiliation: Respiratory Therapy Area, GlaxoSmithKline, Stevenage, Herts, United Kingdom.
authors.forename: Jade
authors.initials: J
authors.lastname: Gough
authors.affiliation: Respiratory Therapy Area, GlaxoSmithKline, Stevenage, Herts, United Kingdom.
authors.forename: Roberto
authors.initials: R
authors.lastname: Solari
mesh_terms: D019943:Amino Acid Substitution; D000818:Animals; D015153:Blotting, Western; D017252:CD3 Complex / Q000276:immunology / Q000378:metabolism; D016207:Cytokines / Q000276:immunology / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000276:immunology / Q000627:therapeutic use; D005260:Female; D005434:Flow Cytometry; D007074:Immunoglobulin G / Q000097:blood / Q000276:immunology; D060889:Inducible T-Cell Co-Stimulator Protein / Q000276:immunology / Q000378:metabolism; D018655:Lymphocyte Count; D008297:Male; D008807:Mice, Inbred BALB C; D018345:Mice, Knockout; D008822:Mice, Transgenic; D010047:Ovalbumin / Q000276:immunology; D011014:Pneumonia / Q000188:drug therapy / Q000235:genetics* / Q000276:immunology; D017354:Point Mutation; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000276:immunology; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000276:immunology / Q000378:metabolism; D013154:Spleen / Q000276:immunology / Q000378:metabolism; D013601:T-Lymphocytes / Q000276:immunology / Q000378:metabolism; D018418:Th2 Cells / Q000276:immunology / Q000378:metabolism
chemical_list: D017252:CD3 Complex; D016207:Cytokines; D004791:Enzyme Inhibitors; C556694:Icos protein, mouse; D007074:Immunoglobulin G; D060889:Inducible T-Cell Co-Stimulator Protein; D016692:Receptors, Antigen, T-Cell, gamma-delta; D010047:Ovalbumin; D011505:Protein-Tyrosine Kinases; C080813:emt protein-tyrosine kinase