Oral Presentations - Federation of Clinical Immunology Societies

S18 Abstracts
F.6 Plasmacytoid Dendritic Cells Induction by a
Self-peptide Ep1.B Derived from Apolipoprotein E
Prevent Autoimmune Diabetes
Enayat Nikoopour, Postdoctoral Fellow, Department of
Microbiology and Immunology and Robarts Research
Institute, London, ON, Canada, Tracey A. Stephens,
Graduate Student, Department of Microbiology and
Immunology and Robarts Research Institute, London, ON,
Canada, Beverley J. Rider, Graduate Student, Department
of Microbiology and Immunology and Robarts Research
Institute, London, ON, Canada, Edwin Lee-Chan, Lab
Technician/Lab Manager, Department of Microbiology and
Immunology and Robarts Research Institute, London, ON,
Canada, Bhagirath Singh, Professor, Department of
Microbiology and Immunology and Robarts Research
Institute, London, ON, Canada
Dendritic cells (DC) are potent inducers of T cell
tolerance. The mechanism by which this is achieved is not
well understood. We postulated that in vivo induction of
plasmacytoid dendritic cells (PDC) could prevent autoimmunity
through induction of T cell tolerance. We report that a
novel self-peptide Ep1.B of mouse Apolipoprotein E (ApoE)
induced differentiation of bone marrow derived monocytes
(BMM) into PDC. In vitro Ep1.B induced PDCs are B220+, Ly6-
C+, CD11c+, mPDCA+, CD62L+ and CD8a+. Footpad injection
of Ep1.B in diabetes prone NOD mice increased the level of
CD11c+, mPDCA and B220+ cells in the draining lymph nodes
(LN) and these CD11c+ cells have an increased expression of
tolerogenic programmed death ligand (PD-L1). Since PD-1-
PD-L1 pathway has been shown to be important in maintaining
tolerance, PDC induced by Ep1.B may inhibit the effector
T cells in disease process. In addition, we found increased
number of CD4+CD25+ T cells with elevated glucocorticoidinduced
tumor necrosis factor receptor related protein
(GITR) in the LN of these animals. We found that injection
of Ep1.B in young NOD mice significantly prevented type 1
diabetes development in these mice. In summary, we suggest
that in vivo Ep1.B induced differentiation of BMM into PDC
that in turn prevented autoimmunity and induced regulatory
T cells in type 1 diabetes prone NOD mice.
doi:10.1016/j.clim.2007.03.219
F.7 Generation and Characterization of Insulin
Peptide-specific Regulatory T Cells
Marianne Martinic, Postdoctoral Fellow, Immune
Regulation Lab DI-3, La Jolla Institute for Allergy and
Immunology, La Jolla, CA, Lisa Togher, Technician, Immune
Regulation Lab DI-3, La Jolla Institute for Allergy and
Immunology, La Jolla, CA, Christophe Filippi, Postdoctoral
Fellow, Immune Regulation Lab DI-3, La Jolla Institute for
Allergy and Immunology, La Jolla, CA, Jean Jasinski, PhD
Student, Barbara Davis Center for Childhood Diabetes,
Aurora, CO, Damien Bresson, Postdoctoral Fellow, Immune
Regulation Lab DI-3, La Jolla Institute for Allergy and
Immunology, La Jolla, CA, George Eisenbarth, Executive
Director, Barbara Davis Center for Childhood Diabetes,
Aurora, CO, Matthias von Herrath, Division Head, Immune
Regulation Lab DI-3, La Jolla Institute for Allergy and
Immunology, La Jolla, CA
Our goal is to generate insulin peptide-specific regulatory
T cells (Tregs) in vitro, which suppress overt diabetes in
prediabetic and reverse already ongoing disease in diabetic
mice. Furthermore we aim to analyze the suppressive
properties and mechanisms of these Tregs in vitro and in
vivo. In order to generate insulin peptide-specific Tregs, we
took advantage of insTCR transgenic mice, which express T
cell receptor (TCR) transgenic CD4+ T cells specific for
the insulinB9–23 peptide (insB) presented on MHC class
II H-2IAg7/d molecules. The in vitro generation of insBspecific
Tregs involved purification of either CD4+CD25+ or
CD4+CD25− insTCR T cells, which were cultured for 1–
2 weeks with the insB peptide, syngeneic antigen presenting
cells and high doses of IL-2 yielding 25+ and 25− cultures,
respectively. Using the classical in vitro suppression assay,
only cells derived from the 25+ cultures were able to
suppress while cells from the 25− cultures enhanced
proliferation and cytokine secretion of CD8+ effector T
cells. In vivo, however, cells from both cultures were unable
to suppress lymphocytic choriomeningitis virus-induced
diabetes. Interestingly, freshly isolated as well as IL-10cultured
CD4+CD25− but not freshly isolated CD4+CD25+
insTCR T cells suppressed spontaneous diabetes in NOD
females. We are currently investigating the mechanisms
underlying the in vivo suppressive potential of these CD4
+CD25− T cells.
doi:10.1016/j.clim.2007.03.220
F.8 The Insulitis Reporter Mouse
Jennifer Ondr, Postdoctoral Fellow, Cincinnati Children’s
Hospital Medical Center, Division of Endocrinology, Diabetes
Research Center, Cincinnati, OH, Robert Opoka, Research
Assistant, Cincinnati Children’s Hospital Medical Center,
Division of Endocrinology, Diabetes Research Center,
Cincinnati, OH, Sankarannand Vukkadapu, Postdoctoral
Fellow, Cincinnati Children’s Research Foundation,
Cincinnati, OH, Jonathan Katz, Associate Professor,
Cincinnati Children’s Hospital Medical Center, Division of
Endocrinology, Diabetes Research Center, Cincinnati, OH
Type 1 diabetes mellitus (T1DM) is caused by the
autoimmune destruction of insulin producing beta cells by
leukocytes that infiltrate the pancreas in a prolonged and
clinically silent process termed insulitis. Inability to detect
insulitis prior to the onset of overt disease symptoms stymies
progress in T1DM research and treatment. In humans,
detection of antibody to islet cell antigens is the only means
to diagnose pre-diabetic insulitis, however, no relationship
between sero-conversion and insulitis progression is established.
In NOD mice, insulitis can be measured, but only as an
end-stage pancreatectomy. An early, accurate diagnosis of
insulitis would allow the possibility of therapeutic intervention,
thus there remains an urgent need for non-invasive and
real-time measures of insulitis. To this end, we are generating
a gene-targeted NOD mouse in which production of a