Artikel
Identification and evaluation of the immunogenic tissue antigens TTR and S100A9 in primary brain tumors by automated two-dimensional protein fractionation
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Autoren
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C. Herold-Mende
- Neurochirurgische Universitätsklinik Heidelberg
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D. Stoycheva
- Neurochirurgische Universitätsklinik Heidelberg
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R. Warta
- HNO-Universitätsklinik Heidelberg
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R. Ahmadi
- Neurochirurgische Universitätsklinik Heidelberg
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P. Beckhove
- DKFZ Heidelberg
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A. Unterberg
- Neurochirurgische Universitätsklinik Heidelberg
| Veröffentlicht: | 20. Mai 2009 |
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Gliederung
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Objective: Identification of antigens that trigger pathogenic T-cell responses in tumors and therefore might serve as antigens used for immunotherapy is still a major challenge of basic and translational immunology. Most methods applied so far are either indirect or restricted to selected HLA-I subtypes and represent complicated and extremely time-consuming procedures.
Methods: We established a new protocol to identify candidate tissue antigens that spontaneously cause T-cell responses in disease situations by using the new automated two-dimensional chromatography system PF2D to fractionate the proteome of tumor tissues. Immunogenicity of protein fractions and whole tumor lysates were tested by ELISPOT assay in an autologous setting. Protein localization of candidate antigens in the corresponding tumor tissue was performed by double immunofluorescence staining.
Results: When fractionating the tumor proteome of an astrocytoma WHO III patient CD4 and CD8 T-cell responses against two novel antigens, transthyretin (TTR) and S100A9 could be identified. Immunogenic epitopes could be identified by using overlapping antigen-specific polypeptides. Immunofluorescent staining revealed that both antigens were expressed on a subpopulation of tumor cells. When expanding this analysis to 10 other brain tumor patients using immunogenic TTR and S100A9 polypeptides, significant T-cell responses were seen in 4/10 cases for TTR and in 3/10 for S100A9. Interestingly, responsiveness to S100A9 was only seen in patients responding to TTR as well. Most importantly, T-cell responsiveness was predominantly seen in high grade tumors.
Conclusions: With TTR and S100A9 we identified two so far unknown immunogenic antigens in primary brain tumors causing T-cell responses in one third of patients analyzed. However, their clinical relevance needs to be further substantiated. Altogether, this fast and cheap method appears to be suitable for identifying additional candidate T-cell antigens which might be suitable for immunotherapy of malignant brain tumors.
