title: APRIL modulates B and T cell immunity.
abstract: The TNF-like ligands APRIL and BLyS are close relatives and share the capacity to bind the receptors TACI and BCMA. BLyS has been shown to play an important role in B cell homeostasis and autoimmunity, but the biological role of APRIL remains less well defined. Analysis of T cells revealed an activation-dependent increase in APRIL mRNA expression. We therefore generated mice expressing APRIL as a transgene in T cells. These mice appeared normal and showed no signs of B cell hyperplasia. Transgenic T cells revealed a greatly enhanced survival in vitro as well as enhanced survival of staphylococcal enterotoxin B-reactive CD4+ T cells in vivo, which both directly correlate with elevated Bcl-2 levels. Analysis of humoral responses to T cell-dependent antigens in the transgenic mice indicated that APRIL affects only IgM but not IgG responses. In contrast, T cell-independent type 2 (TI-2) humoral response was enhanced in APRIL transgenic mice. As TACI was previously reported to be indispensable for TI-2 antibody formation, these results suggest a role for APRIL/TACI interactions in the generation of this response. Taken together, our data indicate that APRIL is involved in the induction and/or maintenance of T and B cell responses.
authors.affiliation: Department of Immunology and Oncology, Centro Nacional de Biotecnología, Madrid, Spain.
authors.forename: Jens V
authors.initials: JV
authors.lastname: Stein
authors.forename: Marta
authors.initials: M
authors.lastname: López-Fraga
authors.forename: Fernando A
authors.initials: FA
authors.lastname: Elustondo
authors.forename: Carla E
authors.initials: CE
authors.lastname: Carvalho-Pinto
authors.forename: Dolores
authors.initials: D
authors.lastname: Rodríguez
authors.forename: Ruth
authors.initials: R
authors.lastname: Gómez-Caro
authors.forename: Joan
authors.initials: J
authors.lastname: De Jong
authors.forename: Carlos
authors.initials: C
authors.lastname: Martínez-A
authors.forename: Jan Paul
authors.initials: JP
authors.lastname: Medema
authors.forename: Michael
authors.initials: M
authors.lastname: Hahne
mesh_terms: D000818:Animals; D000917:Antibody Formation; D001402:B-Lymphocytes / Q000166:cytology / Q000276:immunology*; D002455:Cell Division; D002470:Cell Survival; D015870:Gene Expression; D006801:Humans; D008024:Ligands; D008221:Lymphoid Tissue / Q000276:immunology; D008565:Membrane Proteins / Q000235:genetics / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D013154:Spleen / Q000166:cytology; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology*; D053300:Tumor Necrosis Factor Ligand Superfamily Member 13; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000276:immunology*
chemical_list: D008024:Ligands; D008565:Membrane Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; C114631:TNFSF13 protein, human; C491959:Tnfsf13 protein, mouse; D053300:Tumor Necrosis Factor Ligand Superfamily Member 13; D014409:Tumor Necrosis Factor-alpha