The wild-type sequence (wt) p53(25-35) peptide induces HLA-DR7 and HLA-DR11-restricted CD4+ Th cells capable of enhancing the ex vivo expansion and function of anti-wt p53(264-272) peptide CD8+ T cells.
Tumor peptide-based vaccines are more effective when they include tumor-specific Th cell-defined as well as CTL-defined peptides. Presently, two overlapping wild-type sequences (wt) p53 helper peptides, p53(108-122) and p53(110-124), have been identified as HLA-DR1- and/or HLA-DR4-restricted epitopes. These HLA-DR alleles are expressed by approximately 35% of subjects with cancer. To identify Th cell-defined wt p53 peptides suitable for use on the remaining subject population, a dendritic cell (DC)-based coculture system was developed. CD4+ T cells isolated from PBMC obtained from HLA-DR4- normal donors were stimulated ex vivo with autologous DC transfected with wt p53 or mutant p53 cDNA. Reactivity of T cells was tested in ELISPOT IFN-gamma assays against DC pulsed individually with a panel of algorithm-predicted, multiple HLA-DR-binding wt p53 peptides. The wt p53(25-35) peptide was identified as capable of inducing and being recognized by CD4+ T cells in association, at a minimum, with HLA-DR7 and -DR11 molecules, each of which is expressed by approximately 15% of the population. In addition, the presence of anti-p53(25-35) CD4+ Th cells was shown to enhance the in vitro generation/expansion of HLA-A2-restricted, anti-wt p53(264-272) CD8+ T cells, which from one donor were initially "nonresponsive" to the wt p53(264-272) peptide. The wt p53(25-35) peptide has attributes of a naturally presented Th cell-defined peptide, which could be incorporated into antitumor vaccines applicable to a broader population of subjects for whom a wt p53 helper peptide is presently unavailable, as well as used for monitoring anti-p53 Th cell activity in cancer subjects receiving p53-based immunotherapy.
Ito
Daisuke
D
Division of Basic Research, University of Pittsburgh Cancer Institute, University of Pittsburgh, Pittsburgh, PA 15213, USA.
Albers
Andreas
A
Zhao
Yong Xiang
YX
Visus
Carmen
C
Appella
Ettore
E
Whiteside
Theresa L
TL
DeLeo
Albert B
AB
D000595:Amino Acid Sequence; D000818:Animals; D017951:Antigen Presentation; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology* / Q000378:metabolism*; D002454:Cell Differentiation / Q000276:immunology*; D018920:Coculture Techniques; D003713:Dendritic Cells / Q000276:immunology / Q000378:metabolism; D018984:Epitopes, T-Lymphocyte / Q000378:metabolism / Q000502:physiology; D006684:HLA-DR Antigens / Q000096:biosynthesis / Q000378:metabolism*; D059810:HLA-DR Serological Subtypes; D015809:HLA-DR7 Antigen / Q000096:biosynthesis / Q000378:metabolism*; D006801:Humans; D006825:Hybridomas; D007739:L Cells; D008213:Lymphocyte Activation / Q000276:immunology; D051379:Mice; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000378:metabolism / Q000502:physiology*; D011485:Protein Binding / Q000276:immunology; D006377:T-Lymphocytes, Helper-Inducer / Q000166:cytology / Q000276:immunology* / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism / Q000502:physiology*
D018984:Epitopes, T-Lymphocyte; D006684:HLA-DR Antigens; D059810:HLA-DR Serological Subtypes; C080766:HLA-DR11 antigen; D015809:HLA-DR7 Antigen; D010446:Peptide Fragments; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53; C474136:p53 peptide 264-272, human