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1.  Exogenous loading of a tapasin-dependent peptide onto HLA-B*44:02 can be restored by acid treatment or fixation of target cells 
European journal of immunology  2012;42(6):1417-1428.
Anti-tumor CTLs recognize peptides derived from cellular proteins and presented on MHC class I. One category of peptides recognized by these CTLs is derived from proteins encoded by “cancer-germline” genes, which are specifically expressed in tumors, and therefore represent optimal targets for cancer immunotherapy. Here, we identify an antigenic peptide, which is derived from the MAGE-A1-encoded protein (160-169) and presented to CTLs by HLA-B*44:02. Although this peptide is encoded by MAGE-A1, processed endogenously and presented by tumor cells, the corresponding synthetic peptide is hardly able to sensitize target cells to CTL recognition when pulsed exogenously. Endogenous processing and presentation of this peptide is strictly dependent on the presence of tapasin, which is believed to help peptide loading by stabilizing a peptide-receptive form of HLA-B*44:02. Exogenous loading of the peptide can be dramatically improved by paraformaldehyde fixation of surface molecules or by peptide loading at acidic pH. Either strategy allows efficient exogenous loading of the peptide, presumably by generating or stabilizing a peptide-receptive, empty conformation of the HLA. Altogether, our results indicate a potential drawback of short peptide-based vaccination strategies and offer possible solutions regarding the use of problematic epitopes such as the one described here.
doi:10.1002/eji.201141954
PMCID: PMC3766947  PMID: 22678898
Cytolytic T lymphocytes; MAGE-A1; HLA-B*4402; tumor antigen
2.  Genome-wide association analyses identify 13 new susceptibility loci for generalized vitiligo 
Nature genetics  2012;44(6):676-680.
In previous linkage and genome-wide association studies we identified 17 susceptibility loci for generalized vitiligo. By a second genome-wide association study, meta-analysis, and independent replication study, we have now identified 13 additional vitiligo-associated loci, including OCA2-HERC2, a region of 16q24.3 containing MC1R, a region of chromosome 11q21 near TYR, several immunoregulatory loci including IFIH1, CD80, CLNK, BACH2, SLA, CASP7, CD44, IKZF4, SH2B3, and a region of 22q13.2 where the causal gene remains uncertain. Functional pathway analysis shows that most vitiligo susceptibility loci encode immunoregulatory proteins or melanocyte components that likely mediate immune targeting and genetic relationships among vitiligo, malignant melanoma, and normal variation of eye, skin, and hair color.
doi:10.1038/ng.2272
PMCID: PMC3366044  PMID: 22561518
3.  T-Cell Avidity and Tuning: The Flexible Connection Between Tolerance and Autoimmunity 
International reviews of immunology  2006;25(3-4):235-258.
Thymic T-cell selection mechanisms generate a cross-reactive, self-MHC restricted peripheral T-cell pool. Affinity and avidity are of profound influence on this selection and the generation of immunity. Autoreactive T cells can escape thymic deletion by lowering their avidity and retain this “tuned” state in the periphery. Upon activation, tuned T cells can cause autoimmunity, while immunotherapeutic strategies may be hampered by existing T-cell tolerance. The regulation of T-cell avidity and tuning therefore determines the balance between tolerance and autoimmunity and should be taken into account in the design of therapeutic strategies aimed at T-cell reactivity.
doi:10.1080/08830180600743081
PMCID: PMC3462655  PMID: 16818373
Autoimmunity; avidity; T-cell; Tolerance; Tuning
4.  Therapeutic implications of autoimmune vitiligo T cells 
Autoimmunity reviews  2006;5(7):486-492.
Vitiligo is an autoimmune disease presenting with progressive loss of skin pigmentation. The disease strikes 1% of the world population, generally during teenage years. The progressive loss of melanocytes from depigmenting vitiligo skin is accompanied by cellular infiltrates containing both CD4+ and CD8+ T lymphocytes. Infiltrating cytotoxic T cells with high affinity T cell receptors have likely escaped clonal deletion in the thymus, allowing such T cells to enter the circulation. Through the expression of CLA, these T cells home to the skin where they express type 1-cytokine profiles and mediate melanocyte apoptosis via the granzyme/perforin pathway. T cells found juxtapositionally apposed to remaining melanocytes can be isolated from the skin. Vitiligo T cells have demonstrated reactivity to antigens previously recognized as target antigens for T cells infiltrating melanoma tumors. In a comparison to existing melanoma-derived T cells, vitiligo T cells displayed superior reactivity towards melanoma cells. It is thought that genes encoding the TCRs expressed by vitiligo skin infiltrating T cells can be cloned and expressed in melanoma T cells, thereby generating a pool of circulating T cells with high affinity for their targets that can re-direct the immune response towards the tumor.
doi:10.1016/j.autrev.2006.03.012
PMCID: PMC3462656  PMID: 16920575
Melanocytes; T cells; T cell avidity; T cell receptors; Melanosomes; Antigen presentation
5.  Testing for HLA/peptide tetramer-binding to the T cell receptor complex on human T lymphocytes 
Results in Immunology  2012;2:88-96.
HLA/peptide tetramers are frequently used for ex vivo monitoring of disease- or vaccine-induced T cell immune responses and for T cell epitope identification. However, when low-levels HLA/peptide tetramer-positive T cell populations are encountered, it is difficult to ascertain whether this represents a true T cell receptor (TCR)-mediated interaction or background signal. To address this issue, we have developed a method for both HLA class I and class II tetramer assays to confirm tetramer-binding to the TCR/CD3 complex. Preincubation of T cells with anti-CD3 mAb SPV-T3b and subsequent crosslinking interferes with the binding of HLA/peptide tetramers to the TCR/CD3 complex and thereby indicates to what extent HLA/peptide tetramer binds through interaction with TCR/CD3 complex. SPV-T3b pretreatment results in a 2- to 10-fold decrease in tetramer-binding intensity to antigen-specific CD8+ or CD4+ T cells, whereas background reactivity of HLA/peptide tetramers containing HIV-derived peptide in HIV-negative donors remained unchanged. SPV-T3b pretreatment forms a valuable tool to verify tetramer-based detection of antigen-specific T cells during the monitoring of immune responses in clinical studies.
doi:10.1016/j.rinim.2012.04.001
PMCID: PMC3862383  PMID: 24371571
GAM-Ig, goat anti-mouse immunoglobulin; APC, allophycocyanin; PE, phycoerythrin; mAb, monoclonal antibody; MFI, mean fluorescence intensity; Antigen-specificity; T lymphocytes; HLA/peptide tetramer; Immune response; Patients
6.  Effective Melanoma Immunotherapy in Mice by the Skin-Depigmenting Agent Monobenzone and the Adjuvants Imiquimod and CpG 
PLoS ONE  2010;5(5):e10626.
Background
Presently melanoma still lacks adequate treatment options for metastatic disease. While melanoma is exceptionally challenging to standard regimens, it is suited for treatment with immunotherapy based on its immunogenicity. Since treatment-related skin depigmentation is considered a favourable prognostic sign during melanoma intervention, we here aimed at the reverse approach of directly inducing vitiligo as a shortcut to effective anti-melanoma immunity.
Methodology and Principal Findings
We developed an effective and simple to use form of immunotherapy by combining the topical skin-bleaching agent monobenzone with immune-stimulatory imiquimod cream and cytosine-guanine oligodeoxynucleotides (CpG) injections (MIC therapy). This powerful new approach promptly induced a melanoma antigen-specific immune response, which abolished subcutaneous B16.F10 melanoma growth in up to 85% of C57BL/6 mice. Importantly, this regimen induced over 100 days of tumor-free survival in up to 60% of the mice, and forcefully suppressed tumor growth upon re-challenge either 65- or 165 days after MIC treatment cessation.
Conclusions
MIC therapy is effective in eradicating melanoma, by vigilantly incorporating NK-, B- and T cells in its therapeutic effect. Based on these results, the MIC regimen presents a high-yield, low-cost and simple therapy, readily applicable in the clinic.
doi:10.1371/journal.pone.0010626
PMCID: PMC2869359  PMID: 20498710
7.  Radiation modulates the peptide repertoire, enhances MHC class I expression, and induces successful antitumor immunotherapy 
The Journal of Experimental Medicine  2006;203(5):1259-1271.
Radiotherapy is one of the most successful cancer therapies. Here the effect of irradiation on antigen presentation by MHC class I molecules was studied. Cell surface expression of MHC class I molecules was increased for many days in a radiation dose-dependent manner as a consequence of three responses. Initially, enhanced degradation of existing proteins occurred which resulted in an increased intracellular peptide pool. Subsequently, enhanced translation due to activation of the mammalian target of rapamycin pathway resulted in increased peptide production, antigen presentation, as well as cytotoxic T lymphocyte recognition of irradiated cells. In addition, novel proteins were made in response to γ-irradiation, resulting in new peptides presented by MHC class I molecules, which were recognized by cytotoxic T cells. We show that immunotherapy is successful in eradicating a murine colon adenocarcinoma only when preceded by radiotherapy of the tumor tissue. Our findings indicate that directed radiotherapy can improve the efficacy of tumor immunotherapy.
doi:10.1084/jem.20052494
PMCID: PMC3212727  PMID: 16636135
8.  Identification of MAGE-3 Epitopes Presented by HLA-DR Molecules to CD4+ T Lymphocytes  
MAGE-type genes are expressed by many tumors of different histological types and not by normal cells, except for male germline cells, which do not express major histocompatibility complex (MHC) molecules. Therefore, the antigens encoded by MAGE-type genes are strictly tumor specific and common to many tumors. We describe here the identification of the first MAGE-encoded epitopes presented by histocompatibility leukocyte antigen (HLA) class II molecules to CD4+ T lymphocytes. Monocyte-derived dendritic cells were loaded with a MAGE-3 recombinant protein and used to stimulate autologous CD4+ T cells. We isolated CD4+ T cell clones that recognized two different MAGE-3 epitopes, MAGE-3114–127 and MAGE-3121–134, both presented by the HLA-DR13 molecule, which is expressed in 20% of Caucasians. The second epitope is also encoded by MAGE-1, -2, and -6. Our procedure should be applicable to other proteins for the identification of new tumor-specific antigens presented by HLA class II molecules. The knowledge of such antigens will be useful for evaluation of the immune response of cancer patients immunized with proteins or with recombinant viruses carrying entire genes coding for tumor antigens. The use of antigenic peptides presented by class II in addition to peptides presented by class I may also improve the efficacy of therapeutic antitumor vaccination.
PMCID: PMC2192951  PMID: 10049940
human; invariant chain; peptide; tumor; histocompatibility leukocyte antigen class II

Results 1-8 (8)