Abstract Book 2010 - CIMT Annual Meeting

026 Tanriverdi-Akhisaroglu | Immune monitoring
Spontaneous tumour antigen specific T cell responses occur
frequently in patients with Carcinoma of Unknown
Primary and are predominantly directed against EGFR,
telomerase, MAGE-3 and P53
Serpil Tanriverdi-Akhisaroglu 1 , Harald Löffler 2 , Yingzi Ge 1 , Kim Pietsch 1 , Andreas Bonertz 1 ,
Alwin Krämer 2 , Philipp Beckhove 1
1 Division of Translational Immunology
2 Clinical Cooperation Unit Molecular Hematology/Oncology, German Cancer Research Center, Heidelberg
Introduction: Carcinoma of unknown primary
origin (CUP) represents a so far largely uncharacterized
tumour entity. Since treatment options
and conventional therapy regimens only provide
very limited success (median overall survival of
3-11 months), alternative treatment options need
to be assessed. Tumour immunotherapy has recently
proven clinical efficiency and might provide an
option for the treatment of CUP.
Purpose: As a first basis for the development of
tumour immunotherapy for CUP, we here evaluated,
to what extent CUP patients develop spontaneous
tumour antigen specific T cell responses. In
addition, we characterized the antigen specificities
of tumour-reactive T cells of CUP patients in comparison
to patients with colorectal and pancreatic
carcinoma, as well as breast cancer.
Patients and Methods: We analyzed T cell responses
from peripheral blood of 18 CUP patients. The presence
of tumour antigen specific T cells was assessed
by short term ex vivo IFN-γ ELISPOT assay.
As test antigens, we used a broad panel of long
synthetic peptides derived from immunogenic sequences
of the following defined tumour antigens:
MUC-11-100, MUC-1(1137-157)5, EGFR(479-528),
p53(118-167), Her-2/neu(351-384), CEA(569-618),
Mage3(271-314-157), NYESO1, survivin(93-142),
telomerase(958-1007), heparanase(1-50, 163-212).
As negative control antigen, we used human IgG.
Test or control antigens were loaded on autologous
DCs at a concentration of 200µg/ml and pulsed DCs
were incubated on coated IFN-γ ELISPOT plates for
40 hours. Spots were measured automatically by an
ELISPOT reader and T cell reactivity was assumed
if spot numbers in triplicate test wells were significantly
increased compared to triplicate control
wells. Test results were compared to results of peripheral
blood-derived T cell samples from patients
with pancreatic- , colorectal- or breast cancer or
from healthy volunteers.
Results: Interestingly, we observed in all (100%)
patients pre-existing, tumour antigenspecific T
cells with an average number of 3.4 antigens simultaneously
recognized. This compares favourably to
spontaneous T cell responses detectable in patients
with pancreatic cancer (85%), breast cancer (61%),
colorectal cancer (60%) and strongly exceeded
the minor rates of TA-specific T cell responses in
healthy individuals. CUP patients developed predominant
T cell responses against EGFR (50%),
telomerase (47%), Mage3 (40%) and p53 (39%),
whereas responses against the same peptides were
less frequent in CRC patients (12%,0%,20% and
21%, respectively), pancreatic carcinoma patients
(23%,20%,23% and 26%) and also in breast cancer
patients (47 %,21%, 29% and 41%). Particularly, T
cell responses against telomerase were significantly
increased in CUP patients as compared to the
other defined tumour entities (p=0.03).
Conclusion: CUP patients develop polyvalent T cell
responses against a distinct repertoire of tumour
antigens, particularly against EGFR, telomerase,
MAGE-3 and P53, suggesting that these antigens
may be candidates for antigen specific immunotherapy
against CUP.
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