title: γδ T cells are required for maximal expression of allergic conjunctivitis.
abstract: OBJECTIVE
  To determine the function of γδ T cells in early- and late-phase responses in allergic conjunctivitis.
  
  
  METHODS
  Wild-type (WT) C57BL/6 and γδ T cell-deficient (TCR-δ(-/-)) mice were immunized intraperitoneally and challenged topically for 7 consecutive days with short ragweed pollen. Natural killer T (NKT) and γδ T cell-double-deficient mice were generated by treating TCR-δ(-/-) mice with anti-CD1d antibody. Allergic conjunctivitis was evaluated clinically, and the late-phase response was assessed by histopathology. Cytokine profiles were evaluated by ELISA. The afferent and efferent arms of allergic conjunctivitis were assessed by adoptive transfer of CD4(+) T cells from WT or TCR-δ(-/-) mice into naive TCR-δ(-/-) or WT mice.
  
  
  RESULTS
  TCR-δ(-/-) mice had decreased clinical manifestations of allergic conjunctivitis compared with WT mice. TCR-δ(-/-) mice had decreased eosinophilic infiltration compared with WT mice. TCR-δ(-/-) mice produced less Th2-associated cytokines interleukin (IL)-4, -5, and -13 compared with WT mice. Clinical manifestations of allergic conjunctivitis were lowest in NKT cell-depleted TCR-δ(-/-) mice. However, late-phase allergic conjunctivitis in NKT cell-depleted, TCR-δ(-/-) mice was the same as TCR-δ(-/-) mice. Adoptive transfer of CD4(+) T cells revealed that γδ T cells are needed for the afferent and efferent arms of allergic conjunctivitis.
  
  
  CONCLUSIONS
  γδ T cells are needed for full expression of both the clinical manifestations and the late phase of allergic conjunctivitis. Thus, γδ T cells have an important impact in the expression of allergic conjunctivitis and are a potential therapeutic target in the management of allergic diseases of the ocular surface.
authors.affiliation: Department of Ophthalmology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9057, USA.
authors.forename: Nancy J
authors.initials: NJ
authors.lastname: Reyes
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Mayhew
authors.forename: Peter W
authors.initials: PW
authors.lastname: Chen
authors.forename: Jerry Y
authors.initials: JY
authors.lastname: Niederkorn
mesh_terms: D019264:Adoptive Transfer; D031164:Ambrosia; D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D003233:Conjunctivitis, Allergic / Q000276:immunology*; D016207:Cytokines / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D051379:Mice; D008810:Mice, Inbred C57BL; D055611:Natural Killer T-Cells / Q000276:immunology; D011058:Pollen; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000502:physiology*; D013601:T-Lymphocytes / Q000276:immunology*; D018418:Th2 Cells / Q000276:immunology
chemical_list: D016207:Cytokines; D016692:Receptors, Antigen, T-Cell, gamma-delta