Tec kinase Itk in gammadeltaT cells is pivotal for controlling IgE production in vivo.
In conventional alphabeta T cells, the Tec family tyrosine kinase Itk is required for signaling downstream of the T cell receptor (TCR). Itk also regulates alphabeta T cell development, lineage commitment, and effector function. A well established feature of Itk(-/-) mice is their inability to generate T helper type 2 (Th2) responses that produce IL-4, IL-5, and IL-13; yet these mice have spontaneously elevated levels of serum IgE and increased numbers of germinal center B cells. Here we show that the source of this phenotype is gammadelta T cells, as normal IgE levels are observed in Itk(-/-)Tcrd(-/-) mice. When stimulated through the gammadelta TCR, Itk(-/-) gammadelta T cells produce high levels of Th2 cytokines, but diminished IFNgamma. In addition, activated Itk(-/-) gammadelta T cells up-regulate costimulatory molecules important for B cell help, suggesting that they may directly promote B cell activation and Ig class switching. Furthermore, we find that gammadelta T cells numbers are increased in Itk(-/-) mice, most notably the Vgamma1.1(+)Vdelta6.3(+) subset that represents the dominant population of gammadelta NKT cells. Itk(-/-) gammadelta NKT cells also have increased expression of PLZF, a transcription factor required for alphabeta NKT cells, indicating a common molecular program between alphabeta and gammadelta NKT cell lineages. Together, these data indicate that Itk signaling regulates gammadelta T cell lineage development and effector function and is required to control IgE production in vivo.
Felices
Martin
M
Department of Pathology, University of Massachusetts Medical School, Worcester, MA 01655, USA.
Yin
Catherine C
CC
Kosaka
Yoko
Y
Kang
Joonsoo
J
Berg
Leslie J
LJ
D000818:Animals; D001402:B-Lymphocytes; D019070:Cell Lineage; D016207:Cytokines / Q000096:biosynthesis; D017578:Immunoglobulin Class Switching; D007073:Immunoglobulin E / Q000096:biosynthesis*; D008213:Lymphocyte Activation; D051379:Mice; D018345:Mice, Knockout; D055611:Natural Killer T-Cells / Q000166:cytology; D011505:Protein-Tyrosine Kinases / Q000172:deficiency / Q000276:immunology / Q000502:physiology*; D016693:Receptors, Antigen, T-Cell, alpha-beta; D016692:Receptors, Antigen, T-Cell, gamma-delta; D013601:T-Lymphocytes / Q000166:cytology / Q000201:enzymology*; D018418:Th2 Cells
D016207:Cytokines; D016693:Receptors, Antigen, T-Cell, alpha-beta; D016692:Receptors, Antigen, T-Cell, gamma-delta; D007073:Immunoglobulin E; C089848:Tec protein-tyrosine kinase; D011505:Protein-Tyrosine Kinases; C080813:emt protein-tyrosine kinase