[CANCERRESEARcHst,5265—5268, October15,1994)
Advances in Brief
Identification of MART-i-specific T-Cell Receptors: T Cells Utilizing Distinct TCell
Receptor Variable and Joining Regions Recognize the Same Tumor Epitope
David J. Cole, Daniel P. Well, Peter Shamamlan, Licla Rivoltini, Yutaka Kawakami, Suzanne Topalian,
Christopher Jennings, Slona Ellyahu, Steven A. Rosenberg, and Michael I. Nishlmura1
Surgery Branch, NO.tiOnOJ Cancer Institute, NIH, Bethesda, Mwyland 20892
Abstract
Tumor-specific cytotoxic T lymphocytes (CTLs) can mediate tumor
regression in patients with metastatic melanoma and play a central role in
the Immune response to cancer. The recent Identification of shared mel
anoma antigens has raised the possibifity of a limited melsnoina-speclflc
T-cell receptor (TCR) repertoire, but subsequent studies have been con
troversial and difficult to interpret without knowing which tumor-assod
ateti antigens(TAAs)are beingrecognizedby specificTCRS.However,the
recent cloning ofseveral melanoma TAAs now allows for the Identification
ofthe specifically recognized TAA and Its epitope. We evaluated the TCR
of two clonal CD8' CTL lines, A42 and 1E2, from two HLA-A2@pedents
with metastatic melanoma. Both CTL lines were MART-i spedflc, and
both demonstrate reactivity to the same epitope when presented in an
HLA-A2.1 onntext The TCR genes of the two clones were sequenced. AU
of the productively rearranged A42 TCR fi chain genes were Vfi7/D@32.1/
JfJ2.7IC@32; theTCRa chaingeneswereVa2lIJa42/CaThe1E2TCR @3
chain genes were V@33/DfI1.1/JfJ1.1/Cfi1, and TCR a chains were Va25/
JaM/Ca. This study Is the first report of TCR sequences specific for a
melanoma epitope. These TCR clones may be usefUl for the development
of more effective Immunotheraples and in studies of the mechanism of
T-cell recognition oftumor antigen. They also provide direct evidence that
the immunesystemcan providemorethanone TCRcapableof recogniz
ing a TAA epitope.
Introduction
Melanoma-specific CFLs2 derived from ilLs are capable of mcdi
ating tumor regressions in select patients with metastatic disease
(1—2). In vitro, these T lymphocytes specifically lyse autologous and
allogeneic melanoma cells sharing matched MHC restriction dc
ments, suggesting the recognition of commonly expressed TAM
(3—5).Recently, several different melanoma TAM have been de
scribed based on their recognition by melanoma-specific CTL (6—11).
These antigens are present in the majority of melanoma cell lines and
are also expressed in normal melanocytes (tyrosinase, gplOO, and
MART-i) or testes (MAGE-1, MAGE-3). Although the in vivo sig
nificance of these antigens in the recognition of melanoma by T cells
is yet to be defined, it is clear that CFL can play a centralrole in the
immune response to melanoma.
Antigen specific T-lymphocyte reactivity is provided by the TCR a
and @3 chain heterodimer.Each chain is composed of a variable (V'),
joining (J) and constant (C) region, as well as a diversity (D) region
in the 13chain. The V-J and V-D-J junctions of the a and @3 chains
code for the third complementarity-determining region, which plays
Received 7/27/94; accepted 8/31)94.
Thecostsof publication ofthisarticleweredefrayed inpartbythepayment of page
charges. Thisarticlemusttherefore beherebymarkedadvertisement in accordance with
18 USC. Section 1734 solely to indicatethis fact.
1 To whom requests for reprints should be addressed, at Surgery Branch, National
Cancer Institute, NIH@Building 10,Room 2B04, Bethesda, MD 20892.
2 The abbreviations used are: Cli, cytotoxic T lymphocyte; i'lL, tumor-infiltrating
lymphocyte; MHC, major histocompatibiity complex; TAA, tumor-associated antigen;
cDNA, complementary DNI¼ IFN-'y, -@‘ interferon; PCR, polymerase chain reaction; TCR,
T-cell receptor.
an importantrole in antigenspecificity (12, 13). Antigen recognition
occurs via binding of the TCR to a complex composed of peptide,
derived from an antigenic protein, presented in the context of an MHC
molecule (14, 15).
Until recently the actual identification of the structures of the TCR
and peptideelements involved in T-cell recognitionof tumorantigens
has been problematic. The presence of shared TAA in melanoma
raised the possibility of a limited tumor antigen-specific TCR reper
toire, and led to several conflicting studies of T-cell V gene usage in
bulk TIL cultures (16—19).Even the subsequent use of clonal tumor
reactive T-cell populations has demonstrated limited TCR usage in
some studies (20, 21) and diverse V gene usage in others(22, 23). The
possible recognition of several different tumor antigens by different
T-lymphocyte clones makes the interpretation of these studies diffi
cult without knowing which antigens and specific epitopes are being
recognized. Recent cloning of several melanoma antigens recognized
by T lymphocytes has been reported(6-11). Among these antigens,
the MART-i antigen appearsto be the most prevalentbecause it is
specifically recognized by the large majority of ilL cultures tested
(24). The subsequentidentification of the iinmunodominantpeptide
presented in the context of the MHC class I molecule HLA-A2 now
makes possible the isolation of MART-i epitope-specific T-cell
clones and their T-cdll receptors(24, 25).
In this study we have identified the T-cell receptorsof two T-cell
clones which recognize the same MART-i epitope. Each clone uses
different variable and joining regions. These TCR clones may be
useful for the development of more effective adoptive immunothera
pies and in studies of the mechanisms of T-cell recognition of tumor
antigen.They also provide direct evidence thatthe redundancyof the
immune system can provide more than one TCR capable of recog
rnzing a specific epitope on a tumor-associated antigen.
Materials and Methods
Generationof TIL Lines and Clonee.ilL weregenerated fromtumor
biopsies of 2 patients with metastatic melanoma as described previously (2).
clone A42 was established by limiting dilution at 100 cells/well, with a
proliferating frequency of 1:800, and clone 1E2 was established at 1 cell/well
with a proliferating frequency of 1:43. The clones were cultured in round
bottomed microtiter plates with interleukin 2 (120 international units/mI) in the
presence of feeders (1 x 10@allogeneic peripheral blood lymphocytes/well
irradiated to 5000 rads) with weekly stimulation using 1X 10' autologous
irradiated tumor cells/well.
Cell Lines. Melanoma cell lines C32 and MaIme3M; breast carcinoma cell
line MDA231 (American Type Qilture Collection, Rockville, MD); Ewing's
sarcoma cell line RD-ES (M. Tsokos, NIH); COS-7 cells (W. Leonard, NIH);
melanomacelllines397mel,5Olmel,526mel,624mel,677mel,7OSmel, and
888me1 [established in the Surgery Branch/National Cancer Institute labora
tory as descrthed (5)J; and T2 cells (24) were maintained in RPMI with 10%
fetal calf serum.
Peptide Synthesis. Peptides (kindly provided by Drs. K. Sakaguchi and E.
Appella,NIH)weresynthesizedby a solidphasemethodusinga multiple
peptidesynthesizer (ModelAMS422;GilsonCo.,Inc,Worthington, OH)and
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