Costimulation through the inducible costimulator ligand is essential for both T helper and B cell functions in T cell-dependent B cell responses

• Published in: Nature immunology Vol. 4; no. 8; pp. 765 - 772
• Main Authors: Mak, Tak W, Tafuri, Anna, Shahinian, Arda, Yoshinaga, Steve K, Wakeham, Andrew, Boucher, Louis-Martin, Pintilie, Melania, Duncan, Gordon, Gajewska, Beata U, Gronski, Matthew, Eriksson, Urs, Odermatt, Bernhard, Ho, Alexandra, Bouchard, Denis, Whorisky, John S, Jordana, Manel, Ohashi, Pamela S, Pawson, Tony, Bladt, Friedhelm
• Format: Journal Article
• Language: English
• Published: United States Nature Publishing Group 01-08-2003
• Subjects: Animals; Antigens, Differentiation, T-Lymphocyte - immunology; B-Lymphocytes - immunology; Gene Deletion; Immunoglobulin G - immunology; Inducible T-Cell Co-Stimulator Ligand; Inducible T-Cell Co-Stimulator Protein; Lymphocyte Cooperation - immunology; Mice; Proteins - genetics; Proteins - metabolism; T-Lymphocytes, Helper-Inducer - immunology
• ISSN: 1529-2908; 1529-2916
• DOI: 10.1038/ni947

Costimulation through the inducible costimulator (ICOS) and its ligand (ICOSL) is essential for T cell-dependent B cell responses, but the cellular and temporal dynamics underlying its in vivo effects are poorly defined. Here we have shown that Icosl(-/-) and Icos(-/-) mice had similar phenotypes and that ICOS-ICOSL costimulation modulated the early but not late phases of IgG1 affinity maturation. Exploiting the adoptive transfer of T or B cells from primed Icosl(-/-) mice, we provided genetic evidence that costimulation through ICOSL was essential for primary but not secondary helper T cell responses and for the control of both T and B cell activities, resulting in T cell-dependent IgG1 production.