Survivin (80-88)

Intracellular tumor-associated antigens are targeted by antibodies known as T-cell receptor mimic antibodies (TCRm-Abs), which recognize T-cell epitopes with better stabilities and higher affinities than T-cell receptors. However, TCRm-Abs have been proven difficult to produce using conventional techniques. Here, we developed TCRm-Abs that recognize the survivin-2B-derived nonamer peptide, AYACNTSTL (SV2B80-88), presented on HLA-A*24 (SV2B80-88/HLA-A*24) from immunized mice by using a fluorescence-activated cell sorting-based antigen-specific plasma cells isolation method combined with a high-throughput single-cell-based immunoglobulin-gene-cloning technology. This approach yielded a remarkable efficiency in generating candidate antibody clones that recognize SV2B80-88/HLA-A*24. The screening of the antibody clones for their affinity and ability to bind key amino-acid residues within the target peptide revealed that one clone, #21-3, specifically recognized SV2B80-88/HLA-A*24 on T2 cells. The specificity of #21-3 was further established through survivin-2B-positive tumor cell lines that exogenously or endogenously express HLA-A*24. A bispecific T-cell engager comprised of #21-3 and anti-CD3 showed specific cytotoxicity towards cells bearing SV2B80-88/HLA-A*24 by recruiting and activating T-cells in vitro. The efficient development of TCRm-Ab overcomes the limitations that hamper antibody-based immunotherapeutic approaches and enables the targeting of intracellular tumor-associated antigens.

Background: Survivin-2B is reported to be specifically expressed in numerous malignant tissues. Furthermore, survivin-2B includes the epitope peptide (survivin-2B(80-88)) which is capable of binding to HLA-A24. In this study, we evaluated whether survivin-2B could be a novel vaccine target against lung cancer. Method: (1) The differences in the survivin-2B expression between 15 sets of lung cancer tissues and normal lung tissues were investigated using RT-PCR. (2) The expression of survivin-2B was further examined in 42 lung cancer tissues, and the relationship between the expression and clinicopathologic factors was analyzed. (3) To compare the frequency of precursor CTL between survivin-2B positive and negative lung cancer patients, surivivin-2B(80-88) peptide-specific CTL were induced from regional lymph node lymphocytes (LNL) of four HLA-A24 (+) lung cancer patients, in whom two showed a positive survivin-2B expression of lung cancer while another two were negative, after stimulation with surivivin-2B(80-88). Results: Survivin-2B was specifically expressed in lung cancer tissues, and was expressed in 17 of 42 lung cancer tissues (42.9%). Histologically, it was significantly more frequently expressed in squamous cell carcinoma than in adenocarcinoma (p=0.014). The frequency of precursor CTL in LNL was approximately one in 2.0 x 10(7) in patients with survivin-2B expression (-) lung cancer, however, it was one in 5.0 x 10(6) to 6.0 x 10(6) in those with survivin-2B expression (+) lung cancer. Conclusions: Survivin-2B was specifically expressed in lung cancer tissue, and found to specifically elicit a cellular immune response in lung cancer patients and therefore it may be a novel candidate for peptide vaccination.

Malignant tumors pose a public health problem that jeopardizes human life and quality of living. At present, tumor vaccines in clinical research typically are aimed at stimulating the cellular immune response, while more effective vaccines should take into account the synergy between broad spectrum antibodies and high levels of cellular immunity. In this study, epitope peptides (68-81, 95-104, 80-88) of the tumor antigen survivin were chosen as immunogens and supplemented with poly(I:C) and/or MF59 adjuvant to evaluate the immune effects and anti-melanoma activities. The results indicated that poly(I:C) and MF59 could assist the survivin epitope peptide immunogen to control the tumor size, quality, and volume in black melanoma mouse models. Analyses by antibody titering, antibody isotyping and ELISPOT suggested that the adjuvanted immunogen could induce humoral immunity in mice. Poly(I:C) and MF59 combined with survivin peptide 95-104 could effectively induce humoral immunity mediated by type 2 T helper (Th2) cells. This study provides a basis for candidate immunogen design based on survivin and provides support for tumor therapy that can induce a more balanced Th1/Th2 immune response.