title: Interferon-gamma and interleukin-4 reciprocally regulate CD8 expression in CD8+ T cells.
abstract: The CD8 co-receptor can modulate CD8(+) T cell function through its contributions to T cell receptor (TCR) binding and signaling. Here we show that IFN-gamma and IL-4 exert opposing effects on the expression of CD8alpha mRNA and surface CD8 protein during CD8(+) T cell activation. IL-4 caused down-regulation of surface CD8 on ovalbumin (OVA)(257-264)-specific TCR-transgenic OT-I CD8(+) T cells activated with OVA(257-264)-coated antigen presenting cells or polyclonal stimuli, and on wild type CD8(+) T cells activated with polyclonal stimuli. This effect was enhanced in each case when the cells lacked a functional IFN-gamma or IFN-gamma R gene. When WT or IFN-gamma-deficient OT-I CD8(+) T cells were analyzed 9 days after co-injection with control or IL-4-expressing OVA(+) tumor cells into RAG-2(-/-)gamma c(-/-) mice, CD8 levels were highest on WT donor cells from mice that received the control tumor and lowest on IFN-gamma-deficient donor cells from mice that received the IL-4-expressing tumor. The latter CD8(low) cells displayed markedly impaired binding of OVA(257-264)/MHC tetramers and peptide/MHC-dependent degranulation. The data reveal an unexpected role for IFN-gamma in tuning the CD8 co-receptor during primary CD8(+) T cell activation both in vitro and in vivo.
authors.affiliation: Cooperative Research Centre for Vaccine Technology and the Queensland Institute of Medical Research, Brisbane, Queensland 4006, Australia.
authors.forename: Simon H
authors.initials: SH
authors.lastname: Apte
authors.forename: Adriana
authors.initials: A
authors.lastname: Baz
authors.forename: Penny
authors.initials: P
authors.lastname: Groves
authors.forename: Anne
authors.initials: A
authors.lastname: Kelso
authors.forename: Norbert
authors.initials: N
authors.lastname: Kienzle
mesh_terms: D000818:Animals; D016827:CD8 Antigens / Q000378:metabolism*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism*; D017931:DNA Primers / Q000235:genetics; D005434:Flow Cytometry; D005786:Gene Expression Regulation / Q000276:immunology*; D007371:Interferon-gamma / Q000378:metabolism*; D015847:Interleukin-4 / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D010047:Ovalbumin / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000276:immunology*
chemical_list: D016827:CD8 Antigens; D017931:DNA Primers; D015847:Interleukin-4; D007371:Interferon-gamma; D010047:Ovalbumin