AbstractCurrently only limited information is available as to why dominant IgA isotype responses are supported by mucosal T cells in effector tissues. To address this issue directly, γδ and αβ T cells were isolated from the submandibular gland (SMG) of mice as an example of mucosal effector tissues. Freshly isolated CD3+T cells from this tissue contained relatively high numbers of activated cells approximately 10 interleukin‐2 receptor (IL‐2R)+cells and 15 of cells in cycle stages S and G2+ M, of which 25 and 75 were γδ and αβ T cells, respectively. The cytokine‐specific quantitative reverse transcriptase‐polymerase chain reaction and enzyme‐linked immunospot analyses revealed that, although both γδ and αβ T cells were capable of producing an array of Th1 or Th2 cytokines following stimulation via the T cell receptor‐CD3 complex, these mucosal T cells were mainly committed to IL‐5 and IL‐6 expressionin vivo(Th2 type). Both freshly isolated γδ and αβ T cells expressed mRNA and contained IL‐5 and IL‐6 spot‐forming cells (SFC); however, only the latter exhibited high mRNA levels and SFC for a Th1 cytokine (interferon‐γ). Taken together, the results show that freshly isolated CD3+T cells from SMG contain activated γδ and αβ T cells which are programmed to produce IL‐5 and IL‐6. Thus, SMG, an example of an IgA effector tissue, can be characterized as a Th2‐dominant site. However, although both γδ and αβ T cells express cytokine profiles consistent with a Th2 phenotype, only the latter subset with a CD4+CD8−phenotype prov
展开▼
