Characterization of the role of CD8+T cells in breast cancer immunity following mammaglobin-A DNA vaccination using HLA-class-I tetramers.
BACKGROUND
Mammaglobin-A(mam-A) is expressed in over 80% of human breast tumors. We recently reported that mam-A DNA vaccination resulted in breast cancer immunity in a preclinical model. Here we investigated whether mam-A HLA-class-I tetramers could be used to monitor and define the role of CD8(+)cytotoxic T-lymphocytes(CTL) in mediating breast cancer immunity following mam-A DNA vaccination.


METHODS
Mam-A DNA vaccination was performed in HLA-A2(+)huCD8(+ )transgenic mice. HLA-A2 tetramers carrying the immunodominant mamA2.1 peptide were used to monitor CD8(+)CTL. Human breast cancer colonies were developed in immunodeficient SCID-beige mice. ELISPOT was used to correlate frequency of mamA2.1 tetramer(+)CD8(+)T cells and IFN-gamma production [spots per million cells (spm)] in human subjects.


RESULTS
Vaccination of HLA-A2(+)huCD8(+) mice with mam-A DNA vaccine, but not empty vector, led to the expansion of mamA2.1 tetramer(+)CD8(+)T-cells in peripheral blood (<0.5% pre-vaccination compared to >2.0% post-vaccination). CD8(+)T cells from vaccinated mice specifically lysed UACC-812(HLA-A2(+)/mam-A(+), 25% lysis) but not MDA-MB-415(HLA-A2(-)/mam-A(+)) or MCF-7(HLA-A2(+)/mam-A(-)) breast cancer cells. Adoptive transfer of purified CD8(+)T cells from vaccinated mice into immunodeficient SCID-beige mice with established human breast cancer colonies led to tetramer(+)CD8(+ )T-cell infiltration with regression of UACC-812 but not MCF-7 tumors. HLA-A2(+) breast cancer patients revealed increased frequency of mamA2.1 tetramer(+)CD8(+ )T-cells compared to normal controls (2.86 +/- 0.8% vs. 0.71 +/- 0.1%, P = 0.01) that correlated with the IFN-gamma response to mamA2.1 peptide (48.1 +/- 20.9 vs. 2.9 +/- 0.8 spm, P = 0.03).


CONCLUSIONS
CD8(+ )T-cells are crucial in mediating breast cancer immunity following mam-A DNA vaccination. Mam-A HLA-class-I tetramers can be effectively used to monitor development of CD8(+ )T-cells following mam-A vaccination.
Bharat
Ankit
A
Department of Surgery, Washington University School of Medicine, 660 South Euclid Avenue, 3328 CSRB, P.O. Box 8109-3328, St. Louis, MO 63110, USA. bharata@wudosis.wustl.edu
Benshoff
Nicholas
N
Fleming
Timothy P
TP
Dietz
Jill R
JR
Gillanders
William E
WE
Mohanakumar
T
T
D000818:Animals; D001943:Breast Neoplasms / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D019496:Cancer Vaccines / Q000276:immunology*; D003602:Cytotoxicity, Immunologic; D005260:Female; D015789:HLA-A2 Antigen / Q000276:immunology*; D006801:Humans; D060785:Mammaglobin A; D051379:Mice; D008822:Mice, Transgenic; D009363:Neoplasm Proteins / Q000276:immunology*; D014598:Uteroglobin / Q000276:immunology*; D019444:Vaccines, DNA / Q000276:immunology*
D019496:Cancer Vaccines; D015789:HLA-A2 Antigen; D060785:Mammaglobin A; D009363:Neoplasm Proteins; C556448:SCGB2A2 protein, human; D019444:Vaccines, DNA; D014598:Uteroglobin