Soluble CD27 as a predictive biomarker for intra-tumoral CD70/CD27 interaction in nasopharyngeal carcinoma.

In CD70-expressing tumors, the interaction of CD70 on tumor cells with its lymphocyte receptor, CD27, is thought to play a role in immunosuppression in the tumor microenvironment and elevated serum levels of soluble CD27 (sCD27). Previous studies showed that CD70 is expressed in nasopharyngeal carcinoma (NPC), an Epstein-Barr virus (EBV)-related malignancy. However, the association between intratumoral CD70/CD27 expression and serum levels of sCD27 in NPC remains unclear. In the present study, we show that CD70 is primarily expressed by tumor cells in NPC and that CD27-positive lymphocytes infiltrate around tumor cells. NPC patients with CD27-positive lymphocytes had significantly better prognosis than patients lacking these cells. In addition, high CD70 expression by tumor cells tended to be correlated with shorter survival in NPC patients with CD27-positive lymphocytes. Serum sCD27 levels were significantly increased in patients with NPC and provided good diagnostic accuracy for discriminating patients from healthy individuals. The concentration of serum sCD27 in patients with CD70-positive NPC with CD27-positive lymphocytes was significantly higher than in patients with tumors negative for CD70 and/or CD27, indicating that the intratumoral CD70/CD27 interaction boosts the release of sCD27. Furthermore, positive expression of CD70 by NPC cells was significantly correlated with EBV infection. Our results suggest that CD70/CD27-targeted immunotherapies may be promising treatment options and that sCD27 may become an essential tool for evaluating the applicability of these therapies by predicting the intratumoral CD70/CD27 interaction in NPC.

A comparison of the clinical efficacy of tonsillectomy with steroid pulse therapy and tonsillectomy therapy alone for patients with immunoglobulin A nephropathy: a retrospective observational study.

BACKGROUND: Tonsillectomy with steroid pulse therapy (TSP) and tonsillectomy monotherapy (T) have improved the prognosis of patients with immunoglobulin A nephropathy (IgAN). However, a consensus has not been reached on the best treatment for these patients. This study aimed to compare the efficacies of TSP and T. METHODS: Data of patients with IgAN who received TSP or T were retrospectively analyzed. The exclusion criterion was a serum creatinine level > 1.5 mg/dL. The clinical remission and renal survival rates were compared. RESULTS: Patients were divided into groups based on the treatment method: the TSP (n = 82) and T groups (n = 41). No significant differences were observed in patient characteristics, except for the observation period (TSP: 60 months, T: 113 months). The log-rank test revealed that the clinical remission rate was significantly higher in the TSP group than in the T group (p < 0.05). The superiority of TSP was also observed in the urinary protein excretion (> / = or < 1 g/day) of the two subgroups. According to the Cox proportional-hazards model, the treatment method and daily urinary protein extraction were independent factors affecting clinical remission. The 10-year renal survival rates in the TSP and T groups were 100% and 92.5%, respectively. The log-rank test revealed a tendency for a higher renal survival rate in the TSP group than in the T group (p = 0.09). CONCLUSION: The clinical remission rate was significantly higher with TSP than with T, regardless of urinary protein levels. TSP tended to have a better renal survival rate than T.

Common Characteristics of Sinonasal Inflammation Associated with IgG4-Related Disease and Other Chronic Inflammatory Diseases: A Retrospective Observational Study.

INTRODUCTION: Immunoglobulin G4-related disease (IgG4-RD) is a systemic inflammatory disease characterized by elevated serum IgG4, tissue infiltration of IgG4-positive cells, and fibrosis. Although a number of IgG4-RD patients show sinonasal involvement, there is little known about sinonasal inflammation associated with IgG4-RD. This study aimed to describe the clinicopathological features of sinonasal inflammation associated with IgG4-RD and to compare with other inflammatory diseases, such as eosinophilic chronic rhinosinusitis (ECRS) and granulomatosis with polyangiitis (GPA). METHODS: A retrospective analysis of clinicopathological features of patients with sinonasal lesions and high serum IgG4 was performed. Patient data were reviewed to determine whether they fulfilled the diagnostic criteria for other inflammatory diseases. RESULTS: Six of 7 patients were diagnosed with IgG4-RD, while 1 patient was diagnosed with GPA. In the 6 patients with IgG4-RD, intranasal findings showed nasal polyps in 3 patients (50%) and nasal crusting in the 3 patients (50%). Computed tomography showed ethmoid sinus involvement in 5 patients (83%). Five of the 6 patients (83%) were diagnosed with IgG4-RD based on nasal biopsy, whereas 1 patient (17%) was diagnosed based on lacrimal gland biopsy. Four patients fulfilled the Japanese epidemiological survey of refractory ECRS (JESREC) criteria. However, none of the patients showed eosinophil infiltration. Although the patient with GPA showed high levels of serum IgG4 and tissue infiltration of IgG4-positive cells in the nasal biopsy, the patient showed common clinical features of GPA. CONCLUSION: Patients with sinonasal inflammation associated with IgG4-RD had similar clinical characteristics with ECRS and GPA. Histopathological findings of the nasal biopsy from clinically diagnosed GPA was consistent with that of IgG4-RD. Sinonasal inflammation associated with IgG4-RD should be diagnosed based not only on tissue infiltration of IgG4-positive cells but in conjunction with clinical findings such as local nasal characteristics, involvement of other organs, and serum antineutrophil cytoplasmic antibody levels. IgG4-RD should be ruled out in patients with eosinophilia without histopathological eosinophil infiltration.

Efficacy of Cetuximab Combined with Paclitaxel in Patients with Recurrent Salivary Gland Carcinoma: A Retrospective Observational Study.

INTRODUCTION: Due to the rarity and various histological types, a standard chemotherapy regimen for recurrent or metastatic salivary gland carcinoma (SGC) has not been established. Molecular-targeted therapy is a novel cancer therapy based on the expression of target molecules. However, few molecular-targeted therapy types have shown satisfactory efficacy for patients with SGC. Our study described promising results of epidermal growth factor receptor (EGFR)-targeting therapy with paclitaxel in patients with SGC. METHODS: The medical records of patients with recurrent SGC treated with weekly cetuximab combined with paclitaxel (Cmab-PTX) between December 2017 and December 2022 at our institutions were retrospectively analyzed. RESULTS: Seven patients with SGC received Cmab-PTX therapy. The median age was 76 years. All patients were high-grade histological types, and EGFR expression was positive in all examined patients. Cmab-PTX was administered for a median period of 20 months (range of 2-36 months). The overall responses were three with complete response, two with partial response, one with stable disease (>24 weeks), and one with progressive disease. The objective response and disease control rates were 71.4% and 85.7%, respectively. Progression-free survival ranged between 2 and 36 months (median 12 months), whereas overall survival ranged between 4 and 111 months (median 36 months). One patient experienced a grade 4 adverse event (neutropenia), which was conservatively manageable. CONCLUSION: Although the treatment sensitivity of SGC with high-grade histological types is usually poor, Cmab-PTX could be a promising treatment regimen for recurrent SGC. Due to the rarity and various histological types, a standard chemotherapy regimen for recurrent or metastatic salivary gland carcinoma (SGC) has not been established. Molecular-targeted therapy is a novel cancer therapy based on the expression of target molecules. However, few molecular-targeted therapy types have shown satisfactory efficacy in patients with SGC. Our study described promising results of cetuximab (Cmab), epidermal growth factor receptor (EGFR)-targeting therapy with paclitaxel (PTX) in patients with SGC. Seven patients with SGC received Cmab-PTX therapy. The median age was 76 years. All patients were high-grade histological types, and EGFR expression was positive in all examined patients. Cmab-PTX was administered for a median period of 20 months. The overall responses were three with complete response, two with partial response, one with stable disease (>24 weeks), and one with progressive disease. The objective response rate was 71.4%. Progression-free survival ranged between 2 and 36 months (median 12 months), whereas overall survival ranged between 4 and 111 months (median 36 months). One patient experienced a grade 4 adverse event (neutropenia), which was conservatively manageable. Our study revealed a preferable objective response rate of Cmab-PTX for patients with high-grade SGC. Although the treatment sensitivity of SGC with high-grade histological types is usually poor, Cmab-PTX could be a promising treatment regimen for recurrent SGC.

Prognostic Value of the 18F-FDG PET/CT and Haematological Parameters in Head and Neck Cancer.

INTRODUCTION: Fluorine 18-fluoro-glucose positron emission tomography/computed tomography (18F-FDG PET/CT) is commonly used for the staging of head and neck cancer. This study aimed to evaluate the correlation between 18F-FDG PET/CT, haematological parameters and prognosis in patients with advanced head and neck cancer. METHODS: This was a single-institutional retrospective study of 83 patients with advanced head and neck squamous cell carcinoma (HNSCC) who underwent 18F-FDG PET/CT imaging before initial treatment between 2014 and 2018. 18F-FDG PET/CT after treatment was performed in 57 patients. The prognostic parameters of the pre- and post-treatment maximum standardised uptake value (SUVmax), metabolic tumour volume (MTV), total lesion glycolysis (TLG) of primary tumours and haematological parameters were analysed to evaluate the association between overall survival (OS) and progression-free survival (PFS). RESULTS: Pre-MTV, pre-TLG and post-SUVmax were significantly associated with poor OS and PFS (p < 0.05). Haematological parameters, including pretreatment neutrophil/lymphocyte ratio and C-reactive protein/albumin ratio, were associated with 18F-FDG PET/CT parameters. In multivariate analysis, post-SUVmax was an independent prognostic factor for OS and PFS. CONCLUSION: A correlation between PET/CT metabolic and haematological parameters was observed. The volume and intensity of 18F-FDG uptake region, in addition to haematological parameters, are feasible markers for predicting the progression of HNSCC in daily practice. Further, post-SUVmax could be an independent parameter for predicting poor survival.

Mitogen-activated protein kinase inhibition augments the T cell response against HOXB7-expressing tumor through human leukocyte antigen upregulation.

Homeobox B7 (HOXB7) is a master regulatory gene that regulates cell proliferation and activates oncogenic pathways. Overexpression of HOXB7 correlates with aggressive behavior and poor prognosis in patients with cancer. However, the expression and role of HOXB7 in head and neck squamous cell carcinoma (HNSCC) remain unclear. In this study, we observed that most samples from patients with oropharyngeal cancer and HNSCC expressed HOXB7. As no direct inhibitor has been reported, we identified a potent peptide epitope to target HOXB7-expressing tumors through immune cells. A novel HOXB7-derived peptide epitope (HOXB78-25 ) elicited antigen-specific and tumor-reactive promiscuous CD4+ T cell responses. These CD4+ T cells produced γ-interferon (IFN-γ) and had the direct ability to kill tumors through granzyme B. Notably, downregulation of HOXB7 using siRNA enhanced human leukocyte antigen class II expression on tumor cells by decreasing the phosphorylation of MAPK. Mitogen-activated protein kinase inhibition augmented IFN-γ production by HOXB7-reactive CD4+ T cell responses without decreasing the expression of HOXB7. These results suggest that combining HOXB7 peptide-based vaccine with MAPK inhibitors could be an effective immunological strategy for cancer treatment.

Brachyury-targeted immunotherapy combined with gemcitabine against head and neck cancer.

Brachyury is a transcription factor belonging to the T-box gene family and is involved in the posterior formation of the mesoderm and differentiation of chordates. As the overexpression of Brachyury is a poor prognostic factor in a variety of cancers, the establishment of Brachyury-targeted therapy would be beneficial for the treatment of aggressive tumors. Because transcription factors are difficult to treat with a therapeutic antibody, peptide vaccines are a feasible approach for targeting Brachyury. In this study, we identified Brachyury-derived epitopes that elicit antigen-specific and tumor-reactive CD4+ T cells that directly kill tumors. T cells recognizing Brachyury epitopes were present in patients with head and neck squamous cell carcinoma. Next, we focused on gemcitabine (GEM) as an immunoadjuvant to augment the efficacy of antitumor responses by T cells. Interestingly, GEM upregulated HLA class I and HLA-DR expression in tumor, followed by the upregulation of anti-tumor T cell responses. As tumoral PD-L1 expression was also augmented by GEM, PD-1/PD-L1 blockade and GEM synergistically enhanced the tumor-reactivity of Brachyury-reactive T cells. The synergy between the PD-1/PD-L1 blockade and GEM was also confirmed in a mouse model of head and neck squamous cell carcinoma. These results suggest that the combined treatment of Brachyury peptide with GEM and immune checkpoint blockade could be a promising immunotherapy against head and neck cancer.

Expression of soluble CD27 in extranodal natural killer/T-cell lymphoma, nasal type: potential as a biomarker for diagnosis and CD27/CD70-targeted therapy.

The engagement of CD27 on lymphocytes with its ligand, CD70, on tumors is believed to mediate tumor immune evasion and the elevation of serum soluble CD27 (sCD27) levels in patients with CD70-positive malignancies. We previously showed that CD70 is expressed in extranodal natural killer/T-cell lymphoma, nasal type (ENKL), an Epstein-Barr virus (EBV)-related malignancy. However, little is known about serum sCD27 expression and its association with the clinical characteristics of, and the CD27/CD70 interaction in, ENKL. In the present study, we show that serum sCD27 is significantly elevated in the sera of patients with ENKL. The levels of serum sCD27 provided excellent diagnostic accuracy for discriminating patients with ENKL from healthy subjects, correlated positively with the levels of other diagnostic markers (lactate dehydrogenase, soluble interleukin-2 receptor, and EBV-DNA), and decreased significantly following treatment. Elevated serum sCD27 levels also correlated significantly with advanced clinical stage and tended to correspond with shorter survival, in patients with ENKL. Immunohistochemistry indicated that CD27-positive tumor-infiltrating immune cells exist adjacent to CD70-positive lymphoma cells. In addition, serum sCD27 levels in patients with CD70-positive ENKL were significantly higher than those in patients with CD70-negative ENKL, suggesting that the intra-tumoral CD27/CD70 interaction boosts the release of sCD27 in serum. Furthermore, the EBV-encoded oncoprotein latent membrane protein 1 upregulated CD70 expression in ENKL cells. Our results suggest that sCD27 may serve as a novel diagnostic biomarker and also may serve as a tool for evaluating the applicability of CD27/CD70-targeted therapies by predicting intra-tumoral CD70 expression and CD27/CD70 interaction in ENKL.

A tumor metastasis-associated molecule TWIST1 is a favorable target for cancer immunotherapy due to its immunogenicity.

Although neoantigens are one of the most favorable targets in cancer immunotherapy, it is less versatile and costly to apply neoantigen-derived cancer vaccines to patients due to individual variation. It is, therefore, important to find highly immunogenic antigens between tumor-specific or associated antigens that are shared among patients. Considering the cancer immunoediting theory, immunogenic tumor cells cannot survive in the early phase of tumor progression including two processes: elimination and equilibrium. We hypothesized that highly immunogenic molecules are allowed to be expressed in tumor cells after an immune suppressive tumor microenvironment was established, if these molecules contribute to tumor survival. In the current study, we focused on TWIST1 as a candidate for highly immunogenic antigens because it is upregulated in tumor cells under hypoxia and promotes tumor metastasis, which is observed in the late phase of tumor progression. We demonstrated that TWIST1 had an immunogenic peptide sequence TWIST1140-162 , which effectively activated TWIST1-specific CD4+ T-cells. In a short-term culture system, we detected more TWIST1-specific responses in breast cancer patients compared with in healthy donors. Vaccination with the TWIST1 peptide also showed efficient expansion of TWIST1-reactive HTLs in humanized mice. These findings indicate that TWIST1 is a highly immunogenic shared antigen and a favorable target for cancer immunotherapy.

A stealth antigen SPESP1, which is epigenetically silenced in tumors, is a suitable target for cancer immunotherapy.

Recent studies have revealed that tumor cells decrease their immunogenicity by epigenetically repressing the expression of highly immunogenic antigens to survive in immunocompetent hosts. We hypothesized that these epigenetically hidden "stealth" antigens should be favorable targets for cancer immunotherapy due to their high immunogenicity. To identify these stealth antigens, we treated human lung cell line A549 with DNA methyltransferase inhibitor 5-aza-2'-deoxycytidine (5Aza) and its prodrug guadecitabine for 3 d in vitro and screened it using cDNA microarray analysis. We found that the gene encoding sperm equatorial segment protein 1 (SPESP1) was re-expressed in cell lines including solid tumors and leukemias treated with 5Aza, although SPESP1 was not detected in untreated tumor cell lines. Using normal human tissue cDNA panels, we demonstrated that SPESP1 was not detected in normal human tissue except for testis and placenta. Moreover, we found using immunohistochemistry SPESP1 re-expression in xenografts in BALB/c-nu/nu mice that received 5Aza treatment. To assess the antigenicity of SPESP1, we stimulated human CD4+ T-cells with a SPESP1-derived peptide designed using a computer algorithm. After repetitive stimulation, SPESP1-specific helper T-cells were obtained; these cells produced interferon-γ against HLA-matched tumor cell lines treated with 5Aza. We also detected SPESP1 expression in freshly collected tumor cells derived from patients with acute myeloid leukemia or lung cancer. In conclusion, SPESP1 can be classified as a stealth antigen, a molecule encoded by a gene that is epigenetically silenced in tumor cells but serves as a highly immunogenic antigen suitable for cancer immunotherapy.

A critical role of STING-triggered tumor-migrating neutrophils for anti-tumor effect of intratumoral cGAMP treatment.

Stimulator of interferon genes (STING) contributes to anti-tumor immunity by activating antigen-presenting cells and inducing mobilization of tumor-specific T cells. A role for tumor-migrating neutrophils in the anti-tumor effect of STING-activating therapy has not been defined. We used mouse tumor transplantation models for assessing neutrophil migration into the tumor triggered by intratumoral treatment with STING agonist, 2'3'-cyclic guanosine monophosphate-adenosine monophosphate (cGAMP). Intratumoral STING activation with cGAMP enhanced neutrophil migration into the tumor in an NF-κB/CXCL1/2-dependent manner. Blocking the neutrophil migration by anti-CXCR2 monoclonal antibody impaired T cell activation in tumor-draining lymph nodes (dLNs) and efficacy of intratumoral cGAMP treatment. Moreover, the intratumoral cGAMP treatment did not show any anti-tumor effect in type I interferon (IFN) signal-impaired mice in spite of enhanced neutrophil accumulation in the tumor. These results suggest that both neutrophil migration and type I interferon (IFN) induction by intratumoral cGAMP treatment were critical for T-cell activation of dLNs and the anti-tumor effect. In addition, we also performed in vitro analysis showing enhanced cytotoxicity of neutrophils by IFN-ß1. Extrinsic STING activation triggers anti-tumor immune responses by recruiting and activating neutrophils in the tumor via two signaling pathways, CXCL1/2 and type I IFNs.

Interruption of MDM2 signaling augments MDM2-targeted T cell-based antitumor immunotherapy through antigen-presenting machinery.

Identification of immunogenic tumor antigens, their corresponding T cell epitopes and the selection of effective adjuvants are prerequisites for developing effective cancer immunotherapies such as therapeutic vaccines. Murine double minute 2 (MDM2) is an E3 ubiquitin-protein ligase that negatively regulates tumor suppressor p53. Because MDM2 overexpression serves as a poor prognosis factor in various types of tumors, it would be beneficial to develop MDM2-targeted cancer vaccines. In this report, we identified an MDM2-derived peptide epitope (MDM232-46) that elicited antigen-specific and tumor-reactive CD4+ T cell responses. These CD4+ T cells directly killed tumor cells via granzyme B. MDM2 is expressed in head and neck cancer patients with poor prognosis, and the T cells that recognize this MDM2 peptide were present in these patients. Notably, Nutlin-3 (MDM2-p53 blocker), inhibited tumor cell proliferation, was shown to augment antitumor T cell responses by increasing MDM2 expression, HLA-class I and HLA-DR through class II transactivator (CIITA). These results suggest that the use of this MDM2 peptide as a therapeutic vaccine combined with MDM2 inhibitors could represent an effective immunologic strategy to treat cancer.

Intratumoral STING activations overcome negative impact of cisplatin on antitumor immunity by inflaming tumor microenvironment in squamous cell carcinoma.

Although cisplatin (CDDP) has been used as a major chemotherapeutic drug for head and neck squamous cell carcinoma (HNSCC), its impact on T-cell functions is controversial. Therefore, we investigated the immunologic effects of CDDP and antitumor effects by combination therapy of CDDP with a ligand for stimulator of interferon genes, cyclic guanosine monophosphate-adenosine monophosphate (cGAMP). Direct impacts of CDDP on T-cell functions were addressed by comparing T-cell functions between human subjects treated and untreated with CDDP. The immune responses and the efficacy of combination therapy using CDDP and cGAMP were assessed using BALB/c mice inoculated with mouse squamous cell carcinoma (SCC) cell lines. CDDP inhibited T-cell proliferation in a dose-dependent manner. T-cell functions of CDDP-treated HNSCC patients were comparable to those of healthy donors and CDDP-untreated HNSCC patients. In the mice bearing SCC cell lines, combination therapy using CDDP and cGAMP enhanced the gene expressions of CXCL9 and CXCL10 in the tumor tissues and inhibited tumor growth. The antitumor effect was cancelled by anti-CXCR3 monoclonal antibody. These findings suggest that the combination therapy using CDDP and an immunomodulating drug like cGAMP would be a rational cancer immunotherapy for patients with HNSCC.

Phosphorylated vimentin as an immunotherapeutic target against metastatic colorectal cancer.

Colorectal cancer (CRC) patients with metastatic lesions have low 5-year survival rates. During metastasis, cancer cells often obtain unique characteristics such as epithelial-mesenchymal transition (EMT). Vimentin a biomarker contributes to EMT by changing cell shape and motility. Since abnormal phosphorylation is a hallmark of malignancy, targeting phosphorylated vimentin is a feasible approach for the treatment of metastatic tumors while sparing non-tumor cells. Recent evidence has revealed that both CD8 cytotoxic T lymphocytes (CTLs) and also CD4 helper T lymphocytes (HTLs) can distinguish post-translationally modified antigens from normal antigens. Here, we showed that the expression of phosphorylated vimentin was upregulated in metastatic sites of CRC. We also showed that a chemotherapeutic reagent augmented the expression of phosphorylated vimentin. The novel phosphorylated helper peptide epitopes from vimentin could elicit a sufficient T cell response. Notably, precursor lymphocytes that specifically reacted to these phosphorylated vimentin-derived peptides were detected in CRC patients. These results suggest that immunotherapy targeting phosphorylated vimentin could be promising for metastatic CRC patients.

Exceptional Response to PD-1 Blockade as First-Line Therapy in Head and Neck Squamous Cell Carcinoma.

The effect of PD-1 blockade as a first-line therapy in nonmetastatic head and neck squamous cell carcinoma (HNSCC) remains unknown. We report a case of an exceptional response to PD-1 blockade as a first-line therapy in a patient with HNSCC and lung cancer. A 59-year-old man presented with cheek swelling and chest pain. He was diagnosed with maxillary sinus carcinoma (squamous cell carcinoma) and lung cancer (non-small-cell lung cancer, not otherwise specified). The maxillary sinus carcinoma was completely resolved after 8 cycles of pembrolizumab. Immune checkpoint blockade warrants further evaluation in previously untreated patients with HNSCC.

Cyclin-dependent kinase 1 and survivin as potential therapeutic targets against nasal natural killer/T-cell lymphoma.

Nasal natural killer/T-cell lymphoma (NNKTL) is closely associated with Epstein-Barr virus (EBV) and is characterized by poor prognosis, resulting from rapid progression of lesions in the affected organs. Recent data have shown that NNKTL is associated with the aberrant expression of cyclin-dependent kinase 1 (CDK1) and its downstream target survivin, but little is known about the functional roles of CDK1 and survivin in NNKTL. In the current study, we show that knockdown of the EBV-encoded oncoprotein latent membrane protein 1 (LMP1) induces downregulation of CDK1 and survivin in NNKTL cells. Immunohistochemistry detected CDK1 and survivin expression in LMP1-positive cells of NNKTL biopsy specimens. Inhibition of CDK1 and survivin in NNKTL cells with several inhibitors led to a dose-dependent decrease in cell proliferation. In addition, the Sp1 inhibitor mithramycin, which can downregulate both CDK1 and survivin, significantly suppressed the growth of established NNKTL in a murine xenograft model. Our results suggest that LMP1 upregulation of CDK1 and survivin may be essential for NNKTL progression. Furthermore, targeting CDK1 and survivin with Sp1 inhibitors such as mithramycin may be an effective approach to treat NNKTL, which is considered to be a treatment-refractory lymphoma.

The route of administration dictates the immunogenicity of peptide-based cancer vaccines in mice.

Vaccines consisting of synthetic peptides representing cytotoxic T-lymphocyte (CTL) epitopes have long been considered as a simple and cost-effective approach to treat cancer. However, the efficacy of these vaccines in the clinic in patients with measurable disease remains questionable. We believe that the poor performance of peptide vaccines is due to their inability to generate sufficiently large CTL responses that are required to have a positive impact against established tumors. Peptide vaccines to elicit CTLs in the clinic have routinely been administered in the same manner as vaccines designed to induce antibody responses: injected subcutaneously and in many instances using Freund's adjuvant. We report here that peptide vaccines and poly-ICLC adjuvant administered via the unconventional intravenous route of immunization generate substantially higher CTL responses as compared to conventional subcutaneous injections, resulting in more successful antitumor effects in mice. Furthermore, amphiphilic antigen constructs such as palmitoylated peptides were shown to be better immunogens than long peptide constructs, which now are in vogue in the clinic. The present findings if translated into the clinical setting could help dissipate the wide-spread skepticism of whether peptide vaccines will ever work to treat cancer.

PD-L1-specific helper T-cells exhibit effective antitumor responses: new strategy of cancer immunotherapy targeting PD-L1 in head and neck squamous cell carcinoma.

BACKGROUND: Head and neck squamous cell carcinoma (HNSCC) originates from squamous epithelium of the upper aerodigestive tract and is the most common malignancy in the head and neck region. Among HNSCCs, oropharynx squamous cell carcinoma (OSCC) has a unique profile and is associated with human papillomavirus infection. Recently, anti-programmed cell death-1 monoclonal antibody has yielded good clinical responses in recurrent and/or metastatic HNSCC patients. Therefore, programmed death-ligand 1 (PD-L1) may be a favorable target molecule for cancer immunotherapy. Although PD-L1-expressing malignant cells could be targeted by PD-L1-specific CD8+ cytotoxic T lymphocytes, it remains unclear whether CD4+ helper T lymphocytes (HTLs) recognize and kill tumor cells in a PD-L1-specific manner. METHODS: The expression levels of PD-L1 and HLA-DR were evaluated using immunohistochemical analyses. MHC class II-binding peptides for PD-L1 were designed based on computer algorithm analyses and added into in vitro culture of HTLs with antigen-presenting cells to evaluate their stimulatory activity. RESULTS: We found that seven of 24 cases of OSCC showed positive for both PD-L1 and HLA-DR and that PD-L1241-265 peptide efficiently activates HTLs, which showed not only cytokine production but also cytotoxicity against tumor cells in a PD-L1-dependent manner. Also, an adoptive transfer of the PD-L1-specific HTLs significantly inhibited growth of PD-L1-expressing human tumor cell lines in an immunodeficient mouse model. Importantly, T cell responses specific for the PD-L1241-265 peptide were detected in the HNSCC patients. CONCLUSIONS: The cancer immunotherapy targeting PD-L1 as a helper T-cell antigen would be a rational strategy for HNSCC patients.

A proliferation-inducing ligand (APRIL) induced hyper-production of IgA from tonsillar mononuclear cells in patients with IgA nephropathy.

IgA nephropathy (IgAN) is a tonsil-related disease. We previously showed that oligodeoxynucleotides with CpG (CpG-ODN) and B-cell activation factor (BAFF) are involved in hyperproduction of IgA from tonsillar mononuclear cells of patients with IgAN (IgAN-TMCs). In this study, we focused on a proliferation-inducing ligand (APRIL), homologous to BAFF. IgAN-TMCs produced more APRIL than non IgAN-TMCs in the presence of both CpG-ODN and control-ODN. TLR9 expression was higher in B-cells of IgAN-TMCs, and treatment with CpG-ODN enhanced transmembrane activator and CAML interactor (TACI) expression. IgA production from IgAN-TMCs was inhibited by APRIL neutralization antibody or TACI blocking antibody, and enhanced by co-treatment of APRIL and CpG-ODN. Serum APRIL levels were higher in patients with IgAN, and decreased after tonsillectomy. These findings suggest that APRIL is involved in the hyperproduction of IgA from IgAN-TMCs, and that CpG-ODN enhanced APRIL-induced IgA production by increasing TACI expression on B-cells of IgAN-TMCs.

Role of MDA5 and interferon-I in dendritic cells for T cell expansion by anti-tumor peptide vaccines in mice.

Cytotoxic T lymphocytes (CTLs) are effective components of the immune system capable of destroying tumor cells. Generation of CTLs using peptide vaccines is a practical approach to treat cancer. We have previously described a peptide vaccination strategy that generates vast numbers of endogenous tumor-reactive CTLs after two sequential immunizations (prime-boost) using poly-ICLC adjuvant, which stimulates endosomal toll-like receptor 3 (TLR3) and cytoplasmic melanoma differentiation antigen 5 (MDA5). Dendritic cells (DCs) play an important role not only in antigen presentation but are critical in generating costimulatory cytokines that promote CTL expansion. Poly-ICLC was shown to be more effective than poly-IC in generating type-I interferon (IFN-I) in various DC subsets, through its enhanced ability to escape the endosomal compartment and stimulate MDA5. In our system, IFN-I did not directly function as a T cell costimulatory cytokine, but enhanced CTL expansion through the induction of IL15. With palmitoylated peptide vaccines, CD8α+ DCs were essential for peptide crosspresentation. For vaccine boosts, non-professional antigen-presenting cells were able to present minimal epitope peptides, but DCs were still required for CTL expansions through the production of IFN-I mediated by poly-ICLC. Overall, these results clarify the roles of DCs, TLR3, MDA5, IFN-I and IL15 in the generation of vast and effective antitumor CTL responses using peptide and poly-IC vaccines.