Generation of mammaglobin-A-specific CD4 T cells and identification of candidate CD4 epitopes for breast cancer vaccine strategies.
BACKGROUND
Mammaglobin-A (MGB) is a breast cancer-associated antigen that is an attractive target for immune intervention. MGB has been shown to induce a specific CD8 T cell response in breast cancer patients, but little is known about a possible MGB-specific CD4 T cell response.


METHODS
Peripheral blood-derived CD4(+)CD25(-) T cells were stimulated in vitro with MGB-pulsed antigen-presenting cells (APC). The MGB and human leukocyte antigen (HLA) class II specificity of the CD4 T cell lines was confirmed by cytokine release following restimulation with autologous and allogenic APC pulsed with MGB from different sources. Candidate HLA class II-restricted epitopes were identified by computer algorithm and validated in cytokine release assays.


RESULTS
MGB-specific CD4 T cells were successfully generated in cultures from six of seven donors. Restimulation of MGB-specific CD4 T cells with MGB-pulsed APC induced significantly higher levels of interferon (IFN)-gamma release than APC pulsed with an irrelevant protein (P = 0.0004). Cultures from five of seven donors showed a pure Th1 type response as evidenced by the absence of interleukin (IL)-4. MGB-specific CD4 T cells recognized both recombinant and naturally processed MGB presented by APC. This recognition was HLA class II-restricted, as HLA-DR mismatched APC were not recognized. MGB-specific CD4 T cells from three of four donors recognized MGB-derived, HLA class II-restricted peptides pulsed onto APC.


CONCLUSIONS
We have successfully generated MGB-specific CD4 T cell cultures and identified candidate MGB HLA class II epitopes. These studies should facilitate study of the CD4 T cell response to MGB, and the development and monitoring of vaccine strategies targeting this unique antigen.
Viehl
Carsten T
CT
Department of Surgery, Washington University School of Medicine, St. Louis, MO 63110, USA.
Frey
Daniel M
DM
Phommaly
Chanpheng
C
Chen
Tingting
T
Fleming
Timothy P
TP
Gillanders
William E
WE
Eberlein
Timothy J
TJ
Goedegebuure
Peter S
PS
D017951:Antigen Presentation / Q000276:immunology; D000951:Antigens, Neoplasm / Q000276:immunology; D001943:Breast Neoplasms / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D019496:Cancer Vaccines; D045744:Cell Line, Tumor; D018984:Epitopes, T-Lymphocyte / Q000276:immunology*; D005260:Female; D000949:Histocompatibility Antigens Class II / Q000276:immunology; D006801:Humans; D008213:Lymphocyte Activation / Q000276:immunology; D060785:Mammaglobin A; D009363:Neoplasm Proteins / Q000276:immunology*; D011994:Recombinant Proteins / Q000276:immunology; D014598:Uteroglobin / Q000276:immunology*
D000951:Antigens, Neoplasm; D019496:Cancer Vaccines; D018984:Epitopes, T-Lymphocyte; D000949:Histocompatibility Antigens Class II; D060785:Mammaglobin A; D009363:Neoplasm Proteins; D011994:Recombinant Proteins; C556448:SCGB2A2 protein, human; D014598:Uteroglobin