title: A co-stimulatory molecule on activated T cells, H4/ICOS, delivers specific signals in T(h) cells and regulates their responses.
abstract: We examined the co-stimulatory activity of H4/ICOS on murine activated CD4(+) T cells and found that the cross-linking of H4/ICOS enhanced their proliferation, in addition to raising IFN-gamma, IL-4 and IL-10 production to levels comparable to those induced by CD28. However, IL-2 production was only marginally co-stimulated by H4/ICOS. This distinct pattern of lymphokine production appears to be induced by a specific intracellular signaling event. Compared with CD28, H4/ICOS dominantly elicited the Akt pathway via phosphatidylinositol 3-kinase. In addition, mitogen-activated protein kinase family kinases were activated in different ways by CD28 and H4/ICOS. The strong phosphorylation of p46 c-Jun N-terminal kinase was observed upon CD28 co-stimulation, but was less potently induced by H4/ICOS. The strain diversity in the induction of H4/ICOS was recognized. The expression of H4/ICOS on BALB/c activated CD4(+) T cells was >6-fold higher compared with C57BL/6 activated CD4(+) T cells. Furthermore, BALB/c activated CD4(+) T cells exhibited more T(h)2-deviated lymphokine production as compared with C57BL/6 activated CD4(+) T cells and signaling through H4/ICOS during the primary stimulation of naive CD4(+) T cells promoted the generation of T(h)2 cells. Thus, the difference in H4/ICOS expression on activated CD4(+) T cells, which is regulated among the mouse strains, may also regulate the polarization of T(h) cells.
authors.affiliation: Departments of Microbiology and Immunology, Tokyo Women's Medical University, 8-1 Kawada-cho, Shinjuku-ku, Tokyo 162-8666, Japan.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Arimura
authors.forename: Hidehito
authors.initials: H
authors.lastname: Kato
authors.forename: Umberto
authors.initials: U
authors.lastname: Dianzani
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Okamoto
authors.forename: Soichiro
authors.initials: S
authors.lastname: Kamekura
authors.forename: Donatella
authors.initials: D
authors.lastname: Buonfiglio
authors.forename: Tohru
authors.initials: T
authors.lastname: Miyoshi-Akiyama
authors.forename: Takehiko
authors.initials: T
authors.lastname: Uchiyama
authors.forename: Junji
authors.initials: J
authors.lastname: Yagi
mesh_terms: D000818:Animals; D000945:Antigens, Differentiation, T-Lymphocyte / Q000378:metabolism*; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology* / Q000378:metabolism; D002454:Cell Differentiation; D005260:Female; D060889:Inducible T-Cell Co-Stimulator Protein; D007371:Interferon-gamma / Q000096:biosynthesis; D016753:Interleukin-10 / Q000096:biosynthesis; D015847:Interleukin-4 / Q000096:biosynthesis; D008213:Lymphocyte Activation; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt; D015398:Signal Transduction; D013045:Species Specificity; D006377:T-Lymphocytes, Helper-Inducer / Q000166:cytology / Q000276:immunology* / Q000378:metabolism; D018417:Th1 Cells / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D018418:Th2 Cells / Q000166:cytology / Q000276:immunology / Q000378:metabolism
chemical_list: D000945:Antigens, Differentiation, T-Lymphocyte; D060889:Inducible T-Cell Co-Stimulator Protein; D007371:Interferon-gamma; D016753:Interleukin-10; D015847:Interleukin-4; D020928:Mitogen-Activated Protein Kinases; D019869:Phosphatidylinositol 3-Kinases; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D051057:Proto-Oncogene Proteins c-akt; C556694:Icos protein, mouse