Polarized Th2 cytokine expression by both mucosal gamma delta and alpha beta T cells.
Currently 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, gamma delta and alpha beta 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 gamma delta and alpha beta T cells, respectively. The cytokine-specific quantitative reverse transcriptase-polymerase chain reaction and enzyme-linked immunospot analyses revealed that, although both gamma delta and alpha beta 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 expression in vivo (Th2 type). Both freshly isolated gamma delta and alpha beta 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-gamma). Taken together, the results show that freshly isolated CD3+ T cells from SMG contain activated gamma delta and alpha beta 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 gamma delta and alpha beta T cells express cytokine profiles consistent with a Th2 phenotype, only the latter subset with a CD4+ CD8- phenotype provided effective help for mucosal B cell responses in vitro.
Hiroi
T
T
Department of Oral Biology, University of Alabama at Birmingham Medical Center 35294-2170, USA.
Fujihashi
K
K
McGhee
J R
JR
Kiyono
H
H
D000818:Animals; D001483:Base Sequence; D017252:CD3 Complex / Q000276:immunology; D016207:Cytokines / Q000096:biosynthesis*; D007070:Immunoglobulin A / Q000096:biosynthesis; D008213:Lymphocyte Activation; D008211:Lymphocyte Cooperation; D051379:Mice; D008809:Mice, Inbred C3H; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000096:biosynthesis; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000032:analysis*; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000032:analysis*; D013363:Submandibular Gland / Q000276:immunology*; D018418:Th2 Cells / Q000276:immunology* / Q000378:metabolism
D017252:CD3 Complex; D016207:Cytokines; D007070:Immunoglobulin A; D012333:RNA, Messenger; D016693:Receptors, Antigen, T-Cell, alpha-beta; D016692:Receptors, Antigen, T-Cell, gamma-delta