CD8 T-cell responses against cyclin B1 in breast cancer patients with tumors overexpressing p53.
OBJECTIVE
This study aimed to examine CD8 T-cell reactivity in breast cancer patients against cyclin B1-derived peptides restricted by the human leukocyte antigen (HLA)-A2 molecule.


METHODS
Peripheral blood mononuclear cells from 36 breast cancer patients were analyzed by enzyme-linked immunosorbent spot (ELISPOT) for the presence of T cells recognizing the cyclin B1-derived peptides CB9 (AKYLMELTM) and CB-P4 (AKYLMELCC), in addition to modified versions of CB9, CB9L2 (ALYLMELTM) and CB9M2 (AMYLMELTM), both of which display higher affinity to HLA-A2.


RESULTS
Twelve patients harbored a memory CD8 T-cell response against at least one of the peptides; strongest reactivity was detected against the CB9L2 peptide. Because the level of cyclin B1 has been shown to be influenced by the level of p53, which in turn is elevated in cancer cells because of point mutation, we analyzed the level of p53 protein in biopsies from the patients by immune histochemistry. Combined data showed that anti-cyclin B1 reactivity was predominantly detected in patients with tumors characterized by elevated expression of p53. Interestingly, no reactivity was detected against six peptides derived from the p53 protein.


CONCLUSIONS
Our data support the notion of cyclin B1 as a prominent target for immunologic recognition in cancer patients harboring p53-mutated cancer cells. Because mutation of p53 is one of the most frequent genetic alterations in human cancers, this suggests that immunotherapy based on targeting of cyclin B1 is broadly applicable in a large proportion of cancer patients.
Sørensen
Rikke Baek
RB
Center for Cancer Immune Therapy, Department of Hematology, University Hospital Herlev, Herlev Ringvej, Denmark.
Andersen
Rikke Sick
RS
Svane
Inge Marie
IM
Engell-Noerregaard
Lotte
L
Hadrup
Sine R
SR
Balslev
Eva
E
Andersen
Mads Hald
MH
thor Straten
Per
P
D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000276:immunology* / Q000473:pathology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D016022:Case-Control Studies; D019926:Cyclin B / Q000276:immunology*; D056744:Cyclin B1; D005260:Female; D005434:Flow Cytometry; D015789:HLA-A2 Antigen / Q000378:metabolism; D006801:Humans; D007124:Immunoenzyme Techniques; D007371:Interferon-gamma / Q000378:metabolism; D008875:Middle Aged; D009154:Mutation; D010446:Peptide Fragments / Q000276:immunology*; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*
C534699:CCNB1 protein, human; D019926:Cyclin B; D056744:Cyclin B1; D015789:HLA-A2 Antigen; D010446:Peptide Fragments; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53; D007371:Interferon-gamma