TY - JOUR
T1 - The cytotoxic T-lymphocyte response against a poorly immunogenic mammary adenocarcinoma is focused on a single immunodominant class I epitope derived from the gp70 Env product of an endogenous retrovirus
AU - Rosato, Antonio
AU - Dalla Santa, Silvia
AU - Zoso, Alessia
AU - Giacomelli, Sofia
AU - Milan, Gabriella
AU - Macino, Beatrice
AU - Tosello, Valeria
AU - Dellabona, Paolo
AU - Lollini, Pier Luigi
AU - De Giovanni, Carla
AU - Zanovello, Paola
PY - 2003/5/1
Y1 - 2003/5/1
N2 - The TS/A mouse mammary adenocarcinoma is a poorly immunogenic tumor widely used in preclinical models of cancer immunotherapy. CTLs have often been indicated as important in TS/A tumor destruction, but their generation in this model has been rarely studied, nor have their precise target(s) been identified. We hypothesized that the gp70 Env product of an endogenous murine leukemia virus could be a target antigen for TS/A-specific CTLs and investigated this possibility in four different TS/A cell lines engineered with the genes that encode IFN-γ, IFN-γ interleukin-4, and B7.1, respectively. All tumor cell lines expressed gp70, albeit at different levels, as demonstrated by reverse transcription-PCR analysis. Transfected tumor cells exhibited a delayed growth in vivo, and partial tumor regression. Spleen cells from mice that displayed tumor regression had high percentages of CD8+ T cells that were specifically stained with Ld tetramers loaded with gp70423-431, the antigenic epitope of gp70 protein. Mixed leukocyte-peptide and mixed leukocyte-tumor cultures, set up by stimulating splenocytes with the immunogenic peptide and with transfected TS/A tumor cells, respectively, resulted in similar large increases in tetramer-reactive CD8+ T cells and showed high lytic activity specific for gp70423-431. Finally, in a Cold Target Inhibition assay, lytic activity of a mixed leukocyte-tumor culture was inhibited in an overlapping fashion by both the TS/A line used for restimulation and 293Ld cells loaded with gp70423-431 peptide, but not by 293Ld cells pulsed with an irrelevant H-2 Ld epitope, thus demonstrating that all or most of the cytotoxic activity was directed exclusively against this antigenic epitope.
AB - The TS/A mouse mammary adenocarcinoma is a poorly immunogenic tumor widely used in preclinical models of cancer immunotherapy. CTLs have often been indicated as important in TS/A tumor destruction, but their generation in this model has been rarely studied, nor have their precise target(s) been identified. We hypothesized that the gp70 Env product of an endogenous murine leukemia virus could be a target antigen for TS/A-specific CTLs and investigated this possibility in four different TS/A cell lines engineered with the genes that encode IFN-γ, IFN-γ interleukin-4, and B7.1, respectively. All tumor cell lines expressed gp70, albeit at different levels, as demonstrated by reverse transcription-PCR analysis. Transfected tumor cells exhibited a delayed growth in vivo, and partial tumor regression. Spleen cells from mice that displayed tumor regression had high percentages of CD8+ T cells that were specifically stained with Ld tetramers loaded with gp70423-431, the antigenic epitope of gp70 protein. Mixed leukocyte-peptide and mixed leukocyte-tumor cultures, set up by stimulating splenocytes with the immunogenic peptide and with transfected TS/A tumor cells, respectively, resulted in similar large increases in tetramer-reactive CD8+ T cells and showed high lytic activity specific for gp70423-431. Finally, in a Cold Target Inhibition assay, lytic activity of a mixed leukocyte-tumor culture was inhibited in an overlapping fashion by both the TS/A line used for restimulation and 293Ld cells loaded with gp70423-431 peptide, but not by 293Ld cells pulsed with an irrelevant H-2 Ld epitope, thus demonstrating that all or most of the cytotoxic activity was directed exclusively against this antigenic epitope.
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M3 - Article
C2 - 12727834
AN - SCOPUS:0037728812
VL - 63
SP - 2158
EP - 2163
JO - Journal of Cancer Research
JF - Journal of Cancer Research
SN - 0008-5472
IS - 9
ER -