The initial response of CD4+ IL-4-producing cells.
Naive CD4(+) T cells were reported to produce small amounts of IL-4 in vitro, which are implicated to be sufficient to initiate T(h)2 response in vivo. However, IL-4-producing naive CD4(+) T cells are difficult to study in vivo because they are present in low numbers shortly after the first antigen exposure. Here, we used IL-4/green fluorescence protein (GFP) reporter mice (G4 mice) to track the initial response of CD4(+) IL-4-producing cells. We first established a flow cytometry method to estimate the number of GFP(+) cells. We demonstrated the effectiveness of this method by showing that the responding CD4(+)GFP(+) cells exhibited an activated phenotype, possessed the capacity to express IL-5 and IL-13, but not IFN-gamma mRNA, and showed enhanced levels of GATA3 and c-maf mRNA expression. More importantly, we showed that the cell lines derived from FACS-sorted CD4(+)GFP(+) cells were antigen specific. By using this newly established method, we showed that the majority of responding GFP(+) cells were CD4(+) T cells. Our study provides direct ex vivo evidence to show that a small percent of CD4(+) T cells that have no previous experience of antigenic stimulation might produce IL-4 to initiate T(h)2 response.
Xin
Junping
J
Department of Cell Biology, Loyola University Chicago School of Medicine, Maywood, IL 60153, USA.
Ohmori
Keitaro
K
Nishida
Jun
J
Zhu
Yuechun
Y
Huang
Hua
H
D000818:Animals; D000941:Antigens / Q000276:immunology; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D002469:Cell Separation / Q000379:methods; D005434:Flow Cytometry / Q000379:methods; D050990:GATA3 Transcription Factor / Q000096:biosynthesis / Q000235:genetics; D015870:Gene Expression / Q000276:immunology*; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins; D007114:Immunization; D018793:Interleukin-13 / Q000096:biosynthesis / Q000235:genetics; D015847:Interleukin-4 / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology*; D015848:Interleukin-5 / Q000096:biosynthesis / Q000235:genetics; D008213:Lymphocyte Activation; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D010047:Ovalbumin / Q000276:immunology; D010641:Phenotype; D051257:Proto-Oncogene Proteins c-maf / Q000096:biosynthesis / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis; D011993:Recombinant Fusion Proteins / Q000276:immunology; D018418:Th2 Cells / Q000276:immunology; D013997:Time Factors
D000941:Antigens; D050990:GATA3 Transcription Factor; C494748:Gata3 protein, mouse; D018793:Interleukin-13; D015848:Interleukin-5; C495608:Maf protein, mouse; D051257:Proto-Oncogene Proteins c-maf; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; D015847:Interleukin-4; D010047:Ovalbumin