title: Strongly reduced alloreactivity and long-term survival times of cardiac allografts in Vav1- and Vav1/Vav2-knockout mice.
abstract: Vav proteins mediate T- and B-cell activation by functioning as GTP/GDP exchange factors for small GTPases. We have studied the role of Vav1 and Vav2 in allogeneic T-cell activation, antibody responses and allograft rejection. Alloantigen-induced proliferation of T cells from Vav1- and Vav1/Vav2-knockout (ko) mice was decreased by >90% in a mixed lymphocyte reaction. In whole-blood cultures, Vav deficiency led to markedly impaired T- and B-cell activation. Expansion of Vav1- or Vav1/Vav2-ko T cells (C57BL/6) was reduced after transfer into severe combined immune deficiency/beige recipient mice (BALB/c). After priming with 2,4-dinitrophenyl (DNP)-keyhole limpet hemocyanin, T-cell-dependent anti-DNP IgM and IgG antibody levels were normal in Vav1-ko mice but undetectable in Vav1/Vav2-ko mice. The median survival time of BALB/c cardiac allografts transplanted into C57BL/6 Vav1-ko mice (n = 13) or Vav1/Vav2-ko mice (n = 5) was >100 and >77 days, compared with 8-9 days in the corresponding wild-type mice. Vav1/Vav2-ko mice with <100 days graft survival developed bacterial skin infections and were prematurely killed with beating cardiac allograft. Long-term surviving transplants of single and double ko mice showed mild cellular interstitial rejection and mild to severe vascular remodeling. In conclusion, our studies show for the first time that the absence of Vav1 and Vav1/Vav2 in ko mice strongly reduces alloreactivity and results in long-term allograft survival, whereas antibody responses were only affected in Vav1/Vav2 ko mice.
authors.affiliation: Autoimmunity and Transplantation, Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland. gisbert.weckbecker@novartis.com
authors.forename: Gisbert
authors.initials: G
authors.lastname: Weckbecker
authors.forename: Christian
authors.initials: C
authors.lastname: Bruns
authors.forename: Klaus-Dieter
authors.initials: KD
authors.lastname: Fischer
authors.forename: Christoph
authors.initials: C
authors.lastname: Heusser
authors.forename: Jianping
authors.initials: J
authors.lastname: Li
authors.forename: Barbara
authors.initials: B
authors.lastname: Metzler
authors.forename: Randall E
authors.initials: RE
authors.lastname: Morris
authors.forename: Barbara
authors.initials: B
authors.lastname: Nuesslein-Hildesheim
authors.forename: Friedrich
authors.initials: F
authors.lastname: Raulf
authors.forename: Grazyna
authors.initials: G
authors.lastname: Wieczorek
authors.forename: Gerhard
authors.initials: G
authors.lastname: Zenke
mesh_terms: D000818:Animals; D004140:Dinitrophenols / Q000276:immunology; D005260:Female; D006085:Graft Survival / Q000276:immunology; D016027:Heart Transplantation / Q000276:immunology* / Q000473:pathology; D006433:Hemocyanins / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D018345:Mice, Knockout; D051567:Proto-Oncogene Proteins c-vav / Q000235:genetics / Q000502:physiology*; D013601:T-Lymphocytes / Q000276:immunology; D014184:Transplantation, Homologous / Q000276:immunology
chemical_list: D004140:Dinitrophenols; D051567:Proto-Oncogene Proteins c-vav; C496619:Vav1 protein, mouse; C490565:Vav2 protein, mouse; D006433:Hemocyanins; C032808:keyhole-limpet hemocyanin