Haematologica 2003 - Supplements

To explore the possibility of using myeloma cells, which may
contain a multitude of tumor antigens that can stimulate an
increased repertoire of anti-tumor T cells, as the source of tumor
antigens for immunotherapy, myeloma-specific CTLs were
generated from patients by culturing T cells with autologous DCs
pulsed with myeloma freeze-and-thaw cell lysate. These CTL lines
proliferated in response to autologous primary myeloma cells and
DCs pulsed with autologous, but not allogeneic, tumor lysate and
secreted predominantly IFN- and TNF-. The CTLs had strong
cytotoxic activity against autologous tumor lysate-pulsed DCs and
primary myeloma cells. Interestingly, some of the CTLs killed, to a
lesser degree, autologous Id-pulsed DCs and allogeneic myeloma
cells, suggesting that Id was sometimes a part of tumor antigens
present in the tumor lysate and that there were shared tumor
antigens between patients. No killing of autologous peripheral
blood mononuclear cells, purified B cells, or Epstein-Barr virustransformed
B-cell lines was observed. These data demonstrate that
CTLs induced by tumor lysate-pulsed DCs specifically kill
autologous tumor cells, but not normal blood cells, and provide a
rationale for vaccination with tumor cell-pulsed DCs in myeloma
patients.
To evaluate the anti-myeloma effects of specific CTLs in vivo, a
myeloma SCID-hu host was established by inoculation of a
myeloma cell line, ARK-RS, into the implanted human bones in the
mice. After myeloma was established, defined by the appearance in
mouse serum of human Ig secreted by the tumor cells, an ARK-RSspecific
CTL line was injected into the tumor sites. Adoptive
transfer of specific T cells, but not control CTLs, strongly
suppressed tumor growth in vivo. Eight weeks after tumor
inoculation, control mice and mice received control CTLs had large
tumors (5-10 g) around the implanted human bones, while specific
CTL-treated mice had no visible tumor mass or circulating human
Ig. Two weeks after the final injection, circulating human T cells
were still detected in the circulation, indicating that human T cells
survived in the host. These findings indicate that myeloma-specific
CTLs can control or even eradicate tumor cells in vivo.
In conclusion, our studies demonstrate that Id- and tumor lysatespecific
CTLs can be generated from myeloma patients. These
CTLs killed specifically primary myeloma cells but not normal
blood cells in vitro. Adoptive transfer of myeloma-specific CTLs
could eradicate tumor cells in SCID-hu host. Thus, our studies have
laid the basis for adoptive immunotherapy in myeloma patients
using these CTLs, which may be able to eradicate myeloma cells
without causing tissue damage.
References
Yi Q, Österborg A, Bergenbrant S, Mellstedt H, Holm G, Lefvert
AK. Idiotype-reactive T subsets and tumor load in monoclonal
gammopathies. Blood 86:3043-3049, 1995.
Yi Q, Dabadghao S, Österborg A, Bergenbrant S, Holm G.
Myeloma bone marrow plasma cells: evidence for their capacity as
antigen-presenting cells. Blood 90:1960-1967, 1997.
Wen YJ, Barlogie B, Yi Q. Idiotype-specific cytotoxic T
lymphocytes in multiple myeloma: evidence for their capacity to
lyse autologous primary tumor cells. Blood 97:1750-1755, 2001.
Wen YJ, Min R, Tricot G, Barlogie B, Yi Q. Tumor lysate-specific
cytotoxic T lymphocytes in multiple myeloma: promising effector
cells for immunotherapy. Blood 99:3280-3285, 2002.
Supported by grants from the National Cancer Institute (RO1-
CA96569) and Multiple Myeloma Research Foundation and
McCarty Cancer Foundation, and by Translational Research Grants
from the Leukemia and Lymphoma Society (6548-00 and 6041-
03).
P13.5
VACCIBODIES: A NOVEL APPROACH FOR ID
VACCINATION
Agnete Brunsvik, Inger Sandlie and Bjarne Bogen
Institute of Immunology, University of Oslo, Rikshospitalet, 0027
Oslo, Norway. e-mail: bjarne.bogen@labmed.uio.no Bogen lab:
http://www.immunol.net/
Immunoglobulins (Ig) have highly diversified variable (V)
regions that contain unique antigenic determinants called
idiotopes (Id). Idiotype vaccination is promising in treatment of B
cell lymphomas and multiple myelomas, and both anti-idiotypic
antibodies and Id-specific T cells may be of importance (1).
However, Id is a weak self-antigen in its original context (as part
of Ig). Therefore, for vaccine purposes, it is important to enhance
the immunogenicity of Id. To this end, we have now designed a
novel type of recombinant Ig-like molecules called Vaccibodies,
which hopefully induce both strong Id-specific Ab and T cell
responses. The Vaccibodies consist of two scFv’s derived from
the myeloma protein M315 connected through Cγ3 domains and
a hinge to two scFv’s with specificity for MHC class II molecules
expressed on APC (Fig 1).
Fig 1
Legend Fig 1. The structure of the Vaccibody. The two scFvs
(top) target the Vaccibody to surface molecules on APC. The two
patient-derived M-component scFvs are at the bottom. The two
types of Fv are connected by a hinge and C H 3 domains. The
hinge contributes to flexibility of the two NH 2 -terminal scFvs
relative orientation and offers disulfide bridges between the
monomers. The C H 3 domains act as a spacer between the NH 2
and COOH terminal scFvs and participate in the dimerization
through hydrophobic interactions.
Vaccibodies have been prepared for use in the MOPC315 mouse
myeloma model in which Id-specific CD4 + T cells protect mice
against myeloma development (2-5). The Vaccibodies have been
genetically constructed, and transfected NSO cells produce and
secrete the recombinant molecules. The Vaccibodies appear to
have a correct structure. In particular, the scFv’s at each end of
the Vaccibodies exhibit binding to MHC class II and DNP
(specificity of M315), respectively. Thus, the domains retain the
same folding pattern as in their original context. The Vaccibodies
have been constructed to induce strong T cell responses. The
produced Vaccibodies are designed to bind MHC class II + APC
and, subsequent to endocytosis and antigen processing, be
presented as Id-peptides on class II molecules to Id-specific CD4 +
T cells. Furthermore, since they have intact Fv of the M-
component, they should bind anti-Id B cells and, with the help of
Id-specific T cells, induce differentiation of such B cells into
plasma cells that produce anti-Id antibodies. Moreover, the
Vaccibodies lack the Cγ2 domains and hence the FcγR binding
sites, and should therefore exclusively be taken up by MHC class
II and not by FcRs on APC. We have compared class II-specific
Vaccibodies with hapten (NIP)-specific Vaccibodies as a
negative (nontargeted) control. Initial experiments in BALB/c
S86