Haematologica 2003 - Supplements

antigen. 3 This induces high levels of epitope-specific CTL able
to produce IFN and to kill tumor cells. To test operation of
this design in human subjects, we have used an epitope derived
from cytomegalovirus (CMV). The chosen epitope is a focus of
the HLA-A*0201-restricted immune response during a natural
infection with CMV. 4 We have shown that the pDOM-epitope
design induces high levels of responding CTL in HLA-A*0201
transgenic mice, and we are currently vaccinating normal donors
of transplants to raise immunity prior to transfer into
immunosuppressed patients, vulnerable to reactivation or
infection with CMV. For myeloma, we have assessed the preclinical
performance of a vaccine design incorporating an epitope
from a known epitope from a cancer-testis antigen.
Results:
Clinical testing:
So far we have vaccinated the first donor with DNA scFv-FrC
with the scFv derived from the recipient’s tumor. A significant
specific T-cell proliferative response against both FrC and against
the patient’s idiotypic protein was observed to develop at the 16
week time point and to persist for several weeks. The response to
FrC was a memory response with apparent fluctuation of levels of
responding T cells during the injection period, likely due to the
movement of cells to the site of injection. The response to
idiotypic protein rose steadily from week 12 onward with no
significant response to control Ig. The immune cells have been
transferred to the patient during DLI and the patient appears to
be doing well.
Analysis of immune status of patients with myeloma:
To consider extending the approach to a larger number of
patients, we need information on the immune status of myeloma
patients undergoing more conventional chemotherapy. We have
first assessed patients who have undergone autologous stem cell
transplant following high dose melphalan. We have used
conventional tetanus toxoid as a test vaccine to facilitate
comparison of immune responses with those of patients being
vaccinated with the DNA constructs containing the gene
encoding the FrC portion of tetanus toxin. Patients were assessed
from 2-15 months post transplant for their ability to produce
antibody or T cell responses to tetanus toxoid. Most patients
responded with antibody and proliferative responses, and all
reached protective levels of anti-tetanus antibody. In several
patients, IFN-producing cells were detected. While responses
tended to be lower than those of normal subjects or patients with
MGUS, it is encouraging that immune capacity appears to have
recovered during the relatively short post-transplant period.
Cancer testis antigens as potential targets for immune attack:
The P1A antigen is a representative of the cancer-testis group of
tumor antigens, and it provides a useful pre-clinical model for
investigating the potential for immune attack on these proteins. 5
There is a single point mutation at codon 42 which generates an
amino acid change, and this mutation can create a peptide target,
designated AB, for immune attack. Vaccination with the
construct encoding a minimal FrC domain fused to the peptide
sequence (p.DOM-AB) generated high levels of AB peptidespecific
IFN-producing CTL able to kill tumor cells and protect
against challenge. These results set the scene for designing DNA
vaccine incorporating candidate tumor-derived peptide sequences
from the family of cancer testis antigens expressed by myeloma
cells.
1. King CA, Spellerberg MB, Zhu D, Rice J, Sahota SS,
Thompsett AR, Hamblin TJ, Radl J & Stevenson FK. (1998)
DNA vaccines with single chain Fv fused to Fragment C of
tetanus toxin induce protective immunity against lymphoma and
myeloma. Nature Med. 4(11):1282-86.
2. van Baren N, Brasseur F, Godelaine D et al (1999) Genes
encoding tumor-specific antigens are expressed in human
myeloma cells. Blood 94:1156-64.
3. Rice J, Buchan S & Stevenson FK. (2002). Critical
components of a DNA fusion vaccine able to induce protective
cytotoxic T cells against a single epitope of a tumor antigen. J
Immunol 169:3908-3913.
4. Wills MR, Carmichael AJ, Mynard K, Jin X, Weekes MP,
Plachter B & Sissons JG. (1996) the human cytotoxic T-
lymphocyte (CTL) response to cytomegalovirus is dominated by
structural protein pp65:frequency, specificity, and T-cell receptor
usage of pp65-specific CTL. J Virol 70:7569-79.
5. van den Eynde B, Mazarguil H, Lethe B, Laval F & Gairin JE.
(1994) Localization of two cytotoxic T lymphocyte epitopes and
three anchoring residues on a single nonameric peptide that binds
to H-2L d and is recognized by cytotoxic T lymphocytes against
mouse tumor P815. Eur J Imm 24:2740-5.
P13.2
Abstract withdrawn
P13.3
DENDRITIC CELL-BASED IMMUNOTHERAPY IN
MULTIPLE MYELOMA.
Nikhil C. Munshi
Dana Farber Cancer Institute, Harvard Medical School, Boston MA
Myeloablative therapies requiring hematopoietic stem cell
support can induce complete remissions in up to 40% of multiple
myeloma (MM) patients. However, ultimately patients experience
disease progression and there is no cure. Novel therapeutic
interventions for this disease are therefore needed to specifically
target the myeloma cell and its microenvironment. The potential
susceptibility of multiple myeloma to immune based therapy has
been demonstrated in the allogeneic transplantation through graft
versus myeloma effect. A major focus of investigation therefore
has been the use of immune-based therapies in a minimal disease
setting to decrease the risk of relapse and potentially achieve
curative outcomes.
Multiple Myeloma (MM) is associated with a number of
dysfunctions in both humoral and cellular immunity (1).
Abnormalities in immune cell numbers have been associated with
inferior disease prognosis. However, both cellular and humoral
immuine responses have been observed against both viral and
tumor antigens. We have also confirmed improvement in the
immune responsiveness in MM patients following effective
therapy especially high-dose chemotherapy followed by
autologous stem cell transplantation by recovery of uninvolved
immuinoglobulins and by significantly higher frequencies of viral
antigen-specific T cells in the peripheral blood (2). These results
have confirmed optimal time for immunotherapy of MM.
We have investigated various immunotherapeutic approaches
using idiotype as a myeloma-specific antigen. In a clinical
protocol involving 49 patients with minimal disease status
following tandem autologous transplantation, we utilized patientspecific
Id protein coupled with KLH, as a vaccine. The
development of an anti-KLH response confirmed immune
competence of the myeloma patients. Moreover, induction of Idspecific
immune responses including generation of CTL
specifically able to lyse MM cells, and a preliminary evidence of
a survival benefit was observed.
To improve on these results we have investigated the role of
dendritic cells (DCs), the most potent antigen-presenting cells
(APCs) equipped with the necessary co-stimulatory, adhesion and
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