Abstract Book 2010 - CIMT Annual Meeting

013 Babiarova | Therapeutic vaccination
Development of different types of vaccine against WT1
tumor antigen
Katarina Babiarova, Luda Kutinova, Eva Brabcova, Jitka Krystofova, Petr Hainz and Sarka
Nemeckova
Department of Experimental Virology, Institute of Hematology and Blood Transfusion, Prague 2, U Nemocnice 1,
CZ-128 20, Czech Republic
The Wilms’ tumor gene 1 (WT1) encodes a tran-
scription factor, initially identified as a suppressor
in the etiology of Wilms’ tumor. It is expressed at
high levels in a variety of human cancer including
leukemia and various types of solid tumors. WT1
protein has been reported to serve as target antigen
for tumor-specific immune responses.
The aims of this study were to prepare experimental
vaccines of different type against WT1 tumor
antigen and to evaluate their potency in immunotherapy
of tumors in mouse model. We prepared
DNA vaccine pBSC/WT1-GUS based on the fusion
gene β-glucoronidase from E.coli (GUS) which
was shown previously to have superior anti-tumor
effect. We also constructed the viral vaccine P13-
WT1-GUS based on the recombinant vaccinia virus
(rVACV) strain P13 with the expression of fusion
protein WT1-GUS under the control of either earlylate
(H5) or synthetic early-late (E/L) VACV promoters.
Every vaccine contains a fragment of murine
WT1 gene coding for a peptide with the length of
155aa (94.-249.aa) containing several CTL epitopes.
We also used peptide vaccines derived from WT1
with motifs predicted to bind to Db murine MHC
I. The efficacy of these vaccines was tested in the
immunization experiments in mice. The ELISPOT-
IFNγ assay and measurement of the intracellular
IFNγ was used to detect T cell immune response
specific for WT1 peptides. Highest response was
elicited by the RMFPNAPYL peptide. The immunization
of mice either with pBSC/WT1-GUS or P13-
WT1-GUS in combination with WT1 peptide vaccine
P(126-135) as a booster revealed a low WT1 peptide
specific T cell immune response in about 50% of
immunized mice. Similar results were found after
the immunization of mice using combination of all
three types of vaccines. Anti-tumor effect of immunization
with the different combination of our
three vaccines were determined in mouse model of
WT-1 positive tumors induced by the TRAMP-C2
cells. We observed that priming with rVACV based
vaccine combined with booster with RMFPNAPYL
peptide in incomplete Freund adjuvant resulted in
enhancement of the growth of TRAMP-C2 cells in
mice. However immunization with one vaccine
only (P13-WT1-GUS) was able to decelerate the
growth of TRAMP-C2 tumors.
This work was supported by grants NS 10660-3/2009 from IGA
MZ ?R and 78608 from GAUK.
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