Remodeling of the epitope repertoire of a candidate idiotype vaccine by targeting to lysosomal degradation in dendritic cells

Abstract

The generation of efficacious vaccines against self-antigens expressed in tumor cells requires breakage of tolerance, and the refocusing of immune responses toward epitopes for which tolerance may not be established. While the presentation of tumor antigens by mature dendritic cells (mDC) may surpass tolerance, broadening of the antigenic repertoire remains an issue. We report that fusion of the candidate idiotype vaccine IGKV3-20 to the Gly-Ala repeat (GAr) of the Epstein-Barr virus nuclear antigen (EBNA)-1 inhibits degradation by the proteasome and redirects processing to the lysosome. mDCs transduced with a recombinant lentivirus encoding the chimeric idiotype efficiently primed CD4+ and CD8+ cytotoxic T-cell (CTL) responses that lysed autologous blasts expressing IGKV3-20 or pulsed with IGKV3-20 synthetic peptides, and HLA-matched IGKV3-20-positive tumor cell lines. Comparison of the cytotoxic response of CD4+ and CD8+ T lymphocytes activated by mDCs expressing the wild-type or chimeric IGKV3-20 reveled largely non-overlapping epitope repertoires in both CD4+ and CD8+ effectors. Thus, fusion to the GAr may provide an effective means to broaden the immune response to an endogenous protein by promoting the presentation of antigenic epitopes that require a lysosome-dependent processing step.

Multiparametric Analyses of Human PBMCs Loaded Ex Vivo with a Candidate Idiotype Vaccine for HCV-Related Lymphoproliferative Disorders

“…Highly reactive monoclonal antibodies (MAbs) specific for IGKV3-20 idiotype of a subject with HCV infection and type II MC associated NHL have been generated, showing their reactivity with B-cell receptors (BCRs) of lymphoma cells from different patients [21] . Alternatively, the IGKV3-20 idiotype has been proposed as vaccine molecule in order to elicit a humoral/cellular immune response as preventive and/or therapeutic approach against the B cell clone sustaining the HCV-associated NHL [25] .…”

Immunogenomics approaches for vaccine evaluation

“…The variable IGKV3-20 light (VL)-chain is one of the idiotypes most frequently associated with non-Hodgkin Lymphomas (NHL) related to Hepatitis C Virus (HCV) infection (de Re et al, 2000;Charles et al, 2008;Perotti et al, 2008), and has been proposed as a potential target of either passive immune therapy or active vaccine strategy (Martorelli et al, 2012). A multi-parametric analysis has been performed on PBMCs loaded ex vivo with the IGKV3-20 protein, including evaluation of activation markers and co-stimulatory molecules, cytokine pattern, and gene transcriptional profile.…”

1086 IGHV1-69 as a Promising Candidate for the Development of a Shared Immunotherapy to B-cell Lymphomas

“…In this respect, a recent paper from Weng et al, selected the T-cell leukemia/lymphoma 1 (TCL1) oncoprotein as an aberrantly expressed antigen in many B-cell malignancies, including FL, CLL, MCL, DLBCL, and SMZL, and identified TCL1 [71][72][73][74][75][76][77][78] as the minimal epitope that binds to HLA-A*0201. They were able to generate peptide-specific CTLs lines from HLA-A*0201 healthy donors and patients, and these CTLs can efficiently kill lymphoma cell lines and primary human lymphoma cells [63].…”

“…The following virus-derived peptides were used as positive controls: HLA-A*0201-restricted Flu matrix 1 M1 58-66 peptide (GILGFVFTL), -A*0301-restricted EBV EBNA3A-RLR 603-611 (RLRAEAQYK), -A*2402-restricted CMV pp65-QYD 341-349 (QYDPVAALF), and -B*3501 CMV pp65-IPS 123 [76][77][78][79][80][81][82][83][84] ) together with the positive controls were synthesized by fluorenylmethoxycarbonil synthesis (Primm, Milan, Italy), purity (>95%) was determined by reverse-phase high-performance liquid chromatography and verified by mass spectral MALDI-TOF analysis. Peptides were dissolved in DMSO at a concentration of 5 mg/ml and stored at -80°C until use.…”

“…The manipulation of the antigen processing machinery allowed reshaping the Id-specific immune response. Indeed, this strategy induced effective responses to subdominant epitopes that could bypass the tolerance to self antigens expressed in malignant cells [76]. …”