FINAL PROGRAM - Society for Immunotherapy of Cancer

Oral Presentation Abstracts
symptom, not the cause of tumor growth. Tumor infiltrating
lymphocytes reflect cancer-induced inflammation, rather than
immunosurveillance. In contrast, tumors induced by virus infection
escape immunosurveillance by local tolerance.
Key Word: Adoptive therapy.
NOD/SCID IL2RGNULL MICE: A MODEL
FOR HUMAN DENDRITIC CELL-BASED
IMMUNOTHERAPIES
Stefani Spranger 1 , Bernhard Frankenberger 1 , Dolores J. Schendel 1,2
1
Institute of Molecular Immunology, Helmholtz Zentrum Muenchen
– German Research Center for Environmental Health, Muenchen,
Germany
2
Clinical Cooperation Group “Immune Monitoring”, Helmholtz Zentrum
Muenchen – German Research Center for Environmental Health,
Muenchen, Germany
Ex vivo-generated dendritic cell (DC)-based vaccines are a
powerful tool to induce tumor-specific immune responses.
Although several clinical trials have demonstrated the in vivo
capacity of DC to induce antigen-specific T cell responses in cancer
patients, an in vivo model has been missing to compare different
protocols of human DC generation and application as a prelude
to clinical studies. We compared different human-derived DC for
vaccination in a newly developed xenograft mouse model. In this
model, NOD/scid/IL2Rgnull (NSG) mice were reconstituted with
human peripheral blood mononuclear cells (PBMC) and vaccinated
with autologous human-derived mature DC expressing the MART-
1 antigen and prepared using different protocols. As a first step,
two regimens for reconstitution were evaluated for engraftment
rates and activation status of human T cells, leading to the
selection of a 4-week engraftment protocol for vaccine evaluation.
Xenografted NSG mice were vaccinated twice with humanderived
mature DC, comparing a newly developed 3-day protocol
versus a more conventional 7-day protocol. The 3-day mature DC
which were clearly superior at inducing antigen-specific immune
responses in vitro (Burdek et al., 2010) also resulted in increased
immune responses in vivo. In previous studies we investigated the
use of Toll-like receptor (TLR) agonists to generate DC capable
of polarizing Th1/CTL responses in vitro. Use of a maturation
cocktail containing TLR agonists yielded DC secreting high levels
of bioactive IL-12(p70), accompanied by tumor-reactive Th1 and
CTL responses in vitro (Spranger et al., 2010). Consistent with
these observations, vaccination using DC matured with a cocktail
containing a TLR7/8 agonist (R848) resulted in enhanced immune
responses in the NSG mouse model. Based on these results
comparing different DC vaccine variations, we conclude that this
new humanized mouse model enables investigation of human
therapeutic cell reagents in an in vivo setting. In particular, this
model allows in vivo comparisons of different vaccine strategies,
different DC variants, as well as immunogenicity of different
immunizing antigens prior to use in clinical studies.
1. Burdek, M, Spranger, S, Wilde, S, Frankenberger, B, Schendel, DJ, and
Geiger, C. Journal Translational Medicine. 2010; 8:90.
2. Spranger, S, Javorovic, M, Burdek, M, Wilde, S, Mosetter, B, Tippmer,
S, Bigalke, I, Geiger, C, Schendel, DJ, and Frankenberger, B. Journal of
Immunology. 2010; 185:738-747.
Key Words: DC-based vaccine, humanized mouse model.
INTRACRANIAL ADMINISTRATION OF HUMAN
ACTIVATED NK CELLS IN A XENOGENEIC MODEL
OF ORTHOTOPIC GLIOBLASTOMA
Erik Ames 1 , Takeshi Hagino 1 , Frederic A. Gorin 2 , Ruben C. Fragoso 3 ,
William J. Murphy 1,4
1
Dermatology, UC Davis School of Medicine, Sacramento, CA
2
Neurology, UC Davis School of Medicine, Sacramento, CA
3
Radiation Oncology, UC Davis School of Medicine, Sacramento, CA
4
Internal Medicine, UC Davis School of Medicine, Sacramento, CA
Glioblastoma multiforme (GBM) is a highly invasive end-stage
glioma which conveys an extremely poor prognosis. Based on
our in vitro data showing very powerful anti-tumor activity of
cytokine activated human natural killer cells against the GBM cell
line U87MG, we sought to develop a xenograft model of GBM
engraftment into immunocompromised mice which would be
treated with intracranial human NK cells. Establishing human NK
cell xenografts have proven to be notoriously difficult due to
the short lifespan of NK cells, the requirement for exogenous
homeostatic cytokines and the rejection of these cells by the
murine host. We addressed these issues by using NOD-scid-IL2R
KO (NSG) mice which lack functional T, B or NK cells. We also
administered a human IL-15 gene therapy through a hydrodynamic
technique which produces high amounts of IL-15 which can be
detectable in the serum for up to 2 weeks. Human NK cells from
healthy donors were expanded up to 1000-fold using a feeder cell
line. These cells were highly cytotoxic and expressed high levels of
activation markers including NKG2D and TRAIL. We administered
these cells intracranially or intraperitoneal to monitor engraftment.
While rhIL-2 administered every other day significantly increased
NK cell engraftment compared to saline treated controls,
hydrodynamic injection of human IL15-encoding plasmid resulted
in increased engraftment in the brain, spleen, liver, bone marrow
and peritoneal fluid 4 days after injection. Importantly, no overt
toxicities were observed in mice receiving intracranial human NK
cells. This therapy was then applied to a tumor model in which
we injected 5×10 4 U87MG luciferin-labeled human glioblastoma
cells stereotactically into the parenchyma of immobilized
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FINAL PROGRAM • SITC 26 TH ANNUAL MEETING
November 4-6, 2011 • North Bethesda, MD • www.sitcancer.org