LAMP1 targeting of the large T antigen of Merkel cell polyomavirus results in potent CD4 T cell responses and tumor inhibition

Introduction

Most cases of Merkel cell carcinoma (MCC), a rare and highly aggressive type of neuroendocrine skin cancer, are associated with Merkel cell polyomavirus (MCPyV) infection. MCPyV integrates into the host genome, resulting in expression of oncoproteins including a truncated form of the viral large T antigen (LT) in infected cells. These oncoproteins are an attractive target for a therapeutic cancer vaccine.

Methods

We designed a cancer vaccine that promotes potent, antigen-specific CD4 T cell responses to MCPyV-LT. To activate antigen-specific CD4 T cells in vivo, we utilized our nucleic acid platform, UNITE™ (UNiversal Intracellular Targeted Expression), which fuses a tumor-associated antigen with lysosomal-associated membrane protein 1 (LAMP1). This lysosomal targeting technology results in enhanced antigen presentation and potent antigen-specific T cell responses. LTS220A, encoding a mutated form of MCPyV-LT that diminishes its pro-oncogenic properties, was introduced into the UNITE™ platform.

Results

Vaccination with LTS220A-UNITE™ DNA vaccine (ITI-3000) induced antigen-specific CD4 T cell responses and a strong humoral response that were sufficient to delay tumor growth of a B16F10 melanoma line expressing LTS220A. This effect was dependent on the CD4 T cells' ability to produce IFNγ. Moreover, ITI-3000 induced a favorable tumor microenvironment (TME), including Th1-type cytokines and significantly enhanced numbers of CD4 and CD8 T cells as well as NK and NKT cells. Additionally, ITI-3000 synergized with an α-PD-1 immune checkpoint inhibitor to further slow tumor growth and enhance survival.

Conclusions

These findings strongly suggest that in pre-clinical studies, DNA vaccination with ITI-3000, using the UNITE™ platform, enhances CD4 T cell responses to MCPyV-LT that result in significant anti-tumor immune responses. These data support the initiation of a first-in-human (FIH) Phase 1 open-label study to evaluate the safety, tolerability, and immunogenicity of ITI-3000 in patients with polyomavirus-positive MCC (NCT05422781).

Abstract 3564: Vaccination using different platforms encoding HER2-LAMP with heterologous boosting enhances adaptive HER2-specific immunity to enable potent anti-tumor responses

Background: Immune checkpoint blockade (ICB) antibodies have demonstrated that effective induction of T cell responses can elicit tumor regression of different metastatic cancers, although these responses are restricted to certain individuals with specific types of cancer. To enhance these responses, there has been renewed emphasis in developing different types of cancer-specific vaccines to stimulate and direct T cell and B cell immunity to important oncologic targets, such as the oncogene human epidermal growth factor receptor 2 (HER2), which is expressed in ~20% of breast cancers (BC). In our previous work we used a DNA plasmid vaccine targeting HER2, which utilized a lysosome-associated membrane protein 1 (LAMP) domain to traffic HER2 antigen to endolysosomal compartments. We demonstrated that this approach was more effective at eliciting antigen specific CD4+ and CD8+ T cell responses, and provided a significant but limited survival benefit in an endogenous mouse model of HER2+ BC compared to a HER2-wild type vaccine.

Methods: In our current study, we explored the use of this modified antigen construct using different vaccine modalities, including DNA plasmid, adenoviral (Ad), modified vaccinia ankara (MVA), and self-replicating RNA vaccines to identify effective vaccine platforms to elicit HER2-specific immunity and anti-tumor immunity. Additionally, we have tested the combination of these modalities in homologous and heterologous vaccine boosting regimens to determine an optimal strategy to elicit anti-tumor immunity in vivo.

Results: In our studies, plasmid and MVA vectors elicited suboptimal immune priming responses, in comparison to Ad and self-replicating RNA vectors that elicit significant HER2-specific T and B cell responses upon vaccination. While timing of boosting is critical, our results reflect that certain platforms (e.g., plasmid DNA vectors) are capable of homologous boosting capacity, while others (e.g., Ad vectors) elicit more robust T and B cell responses to capsid epitopes, limiting homologous boosting capacity for HER2-specific immunity. Significantly, using an endogenous model of metastatic HER2+ BC, we have found that heterologous vaccination with different HER2-LAMP targeted vectors can elicit significantly augmented HER2-specific T and B cell responses that translated into more effective anti-tumor immunity. This immunity proved capable of eliciting tumor regression in ~80% of vaccinated mice, compared to 0% using homologous HER2-WT plasmid vaccination, 30% using homologous HER2-LAMP plasmid vaccination, or 50% with HER2-WT heterologous vaccination.

Conclusions: These data demonstrate the potential of utilizing heterologous vaccine platforms encoding LAMP-based endolysosomal trafficking vaccines to elicit HER2-specific immunity and effect anti-tumor responses.

Citation Format: Robert D. Marek, Alan Chen, Renhuan Xu, Junping Wei, Tao Wang, Xiao Yang, Gangjun Lei, Teri Heiland, Zachary C. Hartman. Vaccination using different platforms encoding HER2-LAMP with heterologous boosting enhances adaptive HER2-specific immunity to enable potent anti-tumor responses [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3564.

Abstract 2052: LAMP1 targeting of the large T antigen of Merkel cell polyomavirus elicits potent CD4+ T cell responses, tumor inhibition, and provides rationale for first-in-human trial

The majority of Merkel cell carcinomas (MCC), a rare and highly aggressive type of neuroendocrine skin cancer, are associated with Merkel cell polyomavirus (MCPyV) infection. MCPyV integrates into the host genome, resulting in expression of a truncated form of the viral large T antigen (LT) in infected cells and thus making LT an attractive target for therapeutic cancer vaccines. We designed a cancer vaccine that promotes potent, antigen-specific CD4+ T cell responses to MCPγV-LT. To activate antigen-specific CD4+ T cells in vivo, we utilized our nucleic acid platform, UNITE࣪ (UNiversal Intracellular Targeted Expression), which fuses a tumor-associated antigen with lysosomal-associated membrane protein 1 (LAMP1). This lysosomal targeting technology results in enhanced antigen presentation and a balanced T cell response. LTS220A, encoding a mutated form of MCPγV-LT that diminishes its pro-oncogenic properties, was introduced into the UNITE࣪ platform. In pre-clinical studies, vaccination with LTS220A-UNITE࣪ (ITI-3000) induced antigen-specific CD4+ T cells that were sufficient to delay tumor growth, and this effect was dependent on their ability to produce IFNγ. Moreover, ITI-3000 induced a favorable tumor microenvironment (TME), including significantly enhanced numbers of CD4+ and CD8+ T cells as well as NK and NKT cells. These findings strongly suggest that in pre-clinical studies, DNA vaccination using the UNITE࣪ platform enhances CD4+ T cell responses to MCPγV-LT that result in significant anti-tumor immune responses. We are planning a first-in-human (FIH) Phase 1 open-label study to evaluate the safety, tolerability, and immunogenicity of ITI-3000 in patients with polyomavirus-positive MCC. Patients will receive up to four intramuscular vaccinations of 4mg of ITI-3000 using the PharmaJet Stratis® needle-free injection system. The primary objectives will be safety and tolerability, observing dose-limiting toxicities, serious adverse events, standard clinical assessments, and safety laboratory parameters. Immunogenicity of the vaccine will be measured by peripheral blood assessments of T cell activation using ELISpot and flow cytometry assays.

Citation Format: Claire Buchta Rosean, Mohan Karkada, David M. Koelle, Paul Nghiem, Teri Heiland. LAMP1 targeting of the large T antigen of Merkel cell polyomavirus elicits potent CD4+ T cell responses, tumor inhibition, and provides rationale for first-in-human trial [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2052.

Development and Characterization of an HCMV Multi-Antigen Therapeutic Vaccine for Glioblastoma Using the UNITE Platform

Glioblastoma multiforme (GBM) is an aggressive form of brain cancer with a median survival of 15 months that has remained unchanged despite advances in the standard of care. GBM cells express human cytomegalovirus (HCMV) proteins, providing a unique opportunity for targeted therapy. We utilized our UNITE (UNiversal Intracellular Targeted Expression) platform to develop a multi-antigen DNA vaccine (ITI-1001) that codes for the HCMV proteins pp65, gB, and IE-1. The UNITE platform involves lysosomal targeting technology, fusing lysosome-associated membrane protein 1 (LAMP1) with target ntigens. We demonstrate evidence of increased antigen presentation by both MHC-I and -II, delivering a robust antigen-specific CD4 and CD8 T-cell response in addition to a strong humoral response. Using a syngeneic orthotopic GBM mouse model, therapeutic treatment with the ITI-1001 vaccine resulted in ~56% survival of tumor-bearing mice. Investigation of the tumor microenvironment showed significant CD4 infiltration as well as enhanced Th1 and cytotoxic CD8 T activation. Regulatory T cells were also upregulated after ITI-1001 vaccination. In addition, tumor burden negatively correlated with activated interferon (IFN)γ+ CD4 T cells, reiterating the importance of CD4 activation in ITI-1001 efficacy and in identifying treatment responders and non-responders. Further characterization of these two groups showed high infiltration of CD3+, CD4+, and CD8+ T cells in responders compared to non-responders. Thus, we show that vaccination with HCMV antigens using the ITI-1001-UNITE platform generates strong cellular and humoral immune responses, triggering significant antitumor activity, leading to enhanced survival in a mouse model of GBM.

Development and characterization of a HCMV multiantigen therapeutic vaccine for GBM using the UNITE platform

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Background: Glioblastoma (GBM) is an aggressive form of brain cancer with a median survival of 15 months which has remained unchanged despite technological advances in the standard of care. GBM cells specifically express human cytomegalovirus (HCMV) proteins providing a unique opportunity for targeted therapy. Methods: We utilized our UNITE (UNiversal Intracellular Targeted Expression) platform to develop a multi-antigen DNA vaccine (ITI-1001) that codes for the HCMV proteins- pp65, gB and IE-1. The UNITE platform involves lysosomal targeting technology, fusing lysosome-associated protein 1 (LAMP1) with target antigens resulting in increased antigen presentation by MHC-I and II. ELISpot, flow cytometry and ELISA techniques were used to evaluate the vaccine immunogenicity and a syngeneic, orthotopic GBM mouse model that expresses HCMV proteins was used for efficacy studies. The tumor microenvironment studies were done using flow cytometry and MSD assay. Results: ITI-1001 vaccination showed a robust antigen-specific CD4 and CD8 T cell response in addition to a strong humoral response. Using GBM mouse model, therapeutic treatment of ITI-1001 vaccine resulted in ̃56% survival with subsequent long-term immunity. Investigating the tumor microenvironment showed significant CD4 T cell infiltration as well as enhanced Th1 and CD8 T cell activation. Regulatory T cells were also upregulated upon ITI-1001 vaccination and would be an attractive target to further improve this therapy. In addition, tumor burden negatively correlated with number of activated CD4 T cells (CD4 IFNγ+) reiterating the importance of CD4 activation in ITI-1001 efficacy and potentially identifying treatment responders and non-responders. Further characterization of these two groups showed high infiltration of CD3+, CD4+ and CD8+ T cells in responders compared with non- responders along with higher CD8 T cell activation. Conclusions: Thus, we show that vaccination with HCMV antigens using the ITI-1001-UNITE platform generates strong cellular and humoral immune responses, triggering significant anti-tumor activity that leads to enhanced survival in mice with GBM.

Abstract 4585: LAMP1 targeting of the large T antigen of Merkel cell polyomavirus elicits potent CD4+ T cell responses and prevents tumor growth

The majority of Merkel cell carcinomas (MCC), a rare and highly-aggressive type of neuroendocrine skin cancer, are associated with Merkel cell polyomavirus (MCPyV) infection. MCPyV integrates into the host genome, resulting in expression of a truncated form of the viral large T antigen (LT) in infected cells and making LT an attractive target for therapeutic cancer vaccines. While induction of tumor-reactive CD8+ T cells is a major goal of cancer therapy, CD4+ T cells provide essential support to CD8+ T cells by promoting their expression of cytotoxic effector molecules and increasing their migratory capacity. Cytokines secreted by CD4+ T cells, such as IFNγ, can also exert desirable effects on the tumor microenvironment. Therefore, we set out to design a cancer vaccine that promotes potent, antigen-specific CD4+ T cell responses to MCPyV-LT. To activate antigen-specific CD4+ T cells in vivo, we utilized our nucleic acid platform, UNITE (UNiversal Intracellular Targeted Expression), which fuses a tumor-associated antigen with lysosomal-associated membrane protein 1 (LAMP1). This lysosomal targeting technology results in enhanced antigen presentation and a balanced T cell response. LTS220A, encoding a mutated form of MCPyV-LT that abrogates its pro-oncogenic properties, was introduced into the UNITE platform. Intradermal vaccination with LTS220A-UNITE promoted a potent, antigen-specific CD4+ T cell response to MCPyV-LT. Additionally, prophylactic vaccination with LTS220A-UNITE prevented growth of B16F10 tumors expressing LTS220A in 100% of mice. Therefore, we find that DNA vaccination using the UNITE platform enhances CD4+ T cell responses to MCPyV-LT and prevents tumor growth when given prophylactically. Future studies will test the efficacy of LTS220A-UNITE for use as a therapeutic cancer vaccine.

Citation Format: Claire Buchta Rosean, Pratima Sinha, David M. Koelle, Paul Nghiem, Teri Heiland. LAMP1 targeting of the large T antigen of Merkel cell polyomavirus elicits potent CD4+ T cell responses and prevents tumor growth [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 4585.

HER2-LAMP vaccines effectively traffic to endolysosomal compartments and generate enhanced polyfunctional T cell responses that induce complete tumor regression

BACKGROUND

The advent of immune checkpoint blockade antibodies has demonstrated that effective mobilization of T cell responses can cause tumor regression of metastatic cancers, although these responses are heterogeneous and restricted to certain histologic types of cancer. To enhance these responses, there has been renewed emphasis in developing effective cancer-specific vaccines to stimulate and direct T cell immunity to important oncologic targets, such as the oncogene human epidermal growth factor receptor 2 (HER2), expressed in ~20% of breast cancers (BCs).

METHODS

In our study, we explored the use of alternative antigen trafficking through use of a lysosome-associated membrane protein 1 (LAMP) domain to enhance vaccine efficacy against HER2 and other model antigens in both in vitro and in vivo studies.

RESULTS

We found that inclusion of this domain in plasmid vaccines effectively trafficked antigens to endolysosomal compartments, resulting in enhanced major histocompatibility complex (MHC) class I and II presentation. Additionally, this augmented the expansion/activation of antigen-specific CD4+ and CD8+ T cells and also led to elevated levels of antigen-specific polyfunctional CD8+ T cells. Significantly, vaccination with HER2-LAMP produced tumor regression in ~30% of vaccinated mice with established tumors in an endogenous model of metastatic HER2+ BC, compared with 0% of HER2-WT vaccinated mice. This therapeutic benefit is associated with enhanced tumor infiltration of activated CD4+ and CD8+ T cells.

CONCLUSIONS

These data demonstrate the potential of using LAMP-based endolysosomal trafficking as a means to augment the generation of polyfunctional, antigen-specific T cells in order to improve antitumor therapeutic responses using cancer antigen vaccines.

The effect of lysosomal-associated membrane protein-1-targeting of Epstein–Barr virus nuclear antigen 1 (EBNA1) on immune response and tumor growth in preclinical studies

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Background: Epstein-Barr virus (EBV) is an oncogenic γ-herpes virus that infects > 90% of the global population. EBV is the primary cause of infectious mononucleosis and is associated with several epithelial and lymphoid malignancies, including nasopharyngeal carcinoma, gastric carcinoma, non-Hodgkin’s and Hodgkin’s lymphoma. Of these, nasopharyngeal carcinoma is particularly prevalent in East and Southeast Asia and is highly metastatic. Current treatment strategies for nasopharyngeal carcinoma are limited to radiation and chemotherapy, demonstrating a need for new, targeted therapies. Most nasopharyngeal carcinomas express EBNA1, a DNA-binding protein involved in maintenance of the episomal virus genome that is required for EBV latency and associated transformation. Targeting EBNA1 allows for an immunotherapeutic approach, by exploiting the potential of the immune system to recognize tumor cells through their expression of this viral antigen. Methods: We designed a DNA vaccine encoding EBNA1 using the UNITE (UNiversal Intracellular Targeted Expression) platform. The UNITE platform is based in part on lysosomal targeting technology which results in enhanced antigen presentation and a balanced T cell response. Results: We report that the EBNA1-UNITE vaccine induced IFNγ-producing effector memory (EM) CD4+ T and CD8+ T cells with complete rejection of EBNA1-expressing tumors observed in 50% of mice. Mice rejecting tumors were protected from rechallenge with CT26-EBNA1, demonstrating that antigen-specific memory was induced in these animals. Tumor microenvironment (TME) analysis showed vaccine-induced mobilization of effector cells, including tumor infiltration of IL-12-producing type 1 dendritic cells, iNOS-producing M1 macrophages, activated EM CD4+T, and CD8+TNFα+T cells. Furthermore, increased PD-1+CD8+T cells in the TME suggests that a combination strategy with PD-1/PD-L1 blockade may be beneficial in a therapeutic setting. Conclusions: This pre-clinical data suggests that the EBNA1-UNITE vaccine has the potential to be used as an immunotherapeutic agent against EBV-associated cancers.

DDIS-23. CMV-BASED PLASMID DNA VACCINE FOR GBM USING THE UNITE PLATFORM

Glioblastoma (GBM) is an aggressive form of brain cancer with a median survival of 15 months, remaining unchanged in spite of technological advances in the standard of care. The presence of the partial CMV genome, specifically in GBM cells, provides a great opportunity for a targeted therapy. We have utilized our UNITE (UNiversal Intracellular Targeted Expression) platform to build a polyvalent DNA vaccine which includes HCMV proteins, pp65, gB and IE-1. The UNITE platform is based, in part, on a lysosomal targeting technology which can result in increased antigen presentation, a balanced T cell response, and subsequent immunologic benefit. Using an orthotopic GBM mouse model expressing CMV proteins in the CT2A cell line, we have shown up to 45% survival when treated therapeutically with the pp65-IE-1 vaccine. In order to further improve the vaccine’s efficacy, and also to understand the mechanism of action, we are evaluating the post-vaccination tumor microenvironment and testing combination therapies with immune checkpoint inhibitors. Preliminary data on treated tumors suggest an increase in the PD-1 immune checkpoint regulator and a higher number of regulatory T cells. Our immune response evaluation of the polyvalent vaccine in naïve mice showed generation of robust antigen specific T cell activation. The use of multiple antigens in this vaccine makes it better suited to prevent antigen escape by tumor cells. Encouraged by our non-clinical data and the promising outcomes from our collaborators’ clinical trials using pp65 mRNA transfected autologous dendritic cells (ATTAC and ATTAC-II), we are moving forward with a phase I trial. We believe that the immune boost from our UNITE platform combined with deactivation of the immunosuppressive microenvironment by checkpoint inhibition holds a promising treatment against GBM.

Abstract LB-204: DNA vaccine co-expressing Her2/ErbB2 antigen, fused with LAMP, elicits strong antitumor effects in vivo by increasing tumor infiltration with CD8+ T cells

DNA vaccines have emerged as an attractive immunotherapeutic approach against infectious diseases and cancer due to its fast, efficient design and validation. It remains, however, a challenge in clinical settings due to historically low levels of immunogenicity in humans. In order to enhance the immunogenicity of DNA vaccines used as a cancer therapy, we have developed a nucleic acid platform, UNITE (UNiversal Intracellular Targeted Expression), which combines novel delivery methods and adjuvants which complement our lysosomal targeting technology. Fusing a tumor associated antigen (TAA) with the Lysosomal Associated Membrane Protein 1 (LAMP-1), we can activate Ag specific CD4+ T cells by targeting the major histocompatibility complex II compartment. In this study, we selected ErbB2/Her2 as the cancer target because it is a broadly overexpressed and well-characterized oncoantigen.

Mice vaccinated with Her2-LAMP DNA demonstrate robust Her2-specific CD4+ and CD8+ T cells, in addition to antibody responses, which in turn have significant antitumor effect in murine breast and bladder tumor models. Moreover, we demonstrate that the Her2-LAMP vaccine promotes CD8+ T cell tumor infiltration to a greater degree than when compared to a traditional DNA vaccine without LAMP. In summary, we show that UNITE as a nucleic acid platform, can enhance antitumor immunity in vivo.

Citation Format: Renhuan Xu, Teri Heiland. DNA vaccine co-expressing Her2/ErbB2 antigen, fused with LAMP, elicits strong antitumor effects in vivo by increasing tumor infiltration with CD8+ T cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr LB-204.

Next generation immunotherapy for tree pollen allergies

Tree pollen induced allergies are one of the major medical and public health burdens in the industrialized world. Allergen-Specific Immunotherapy (AIT) through subcutaneous injection or sublingual delivery is the only approved therapy with curative potential to pollen induced allergies. AIT often is associated with severe side effects and requires long-term treatment. Safer, more effective and convenient allergen specific immunotherapies remain an unmet need. In this review article, we discuss the current progress in applying protein and peptide-based approaches and DNA vaccines to the clinical challenges posed by tree pollen allergies through the lens of preclinical animal models and clinical trials, with an emphasis on the birch and Japanese red cedar pollen induced allergies.

Safety and long-term immunological effects of CryJ2-LAMP plasmid vaccine in Japanese red cedar atopic subjects: A phase I study

Japanese Red Cedar (JRC) pollen induced allergy affects one third of Japanese and the development of effective therapies remains an unachieved challenge. We designed a DNA vaccine encoding CryJ2 allergen from the JRC pollen and Lysosomal Associated Membrane Protein 1 (LAMP-1) to treat JRC allergy. These Phase IA and IB trials assessed safety and immunological effects of the investigational CryJ2-LAMP DNA vaccine in both non-sensitive and sensitive Japanese expatriates living in Honolulu, Hawaii. In the Phase IA trial, 6 JRC non-sensitive subjects and 9 JRC and/or Mountain Cedar (MC) sensitive subjects were given 4 vaccine doses (each 4mg/1ml) intramuscularly (IM) at 14-day intervals. Nine JRC and/or MC sensitive subjects were given 4 doses (2 mg/0.5 ml) IM at 14-day intervals. The safety and functional biomarkers were followed for 132 d. Following this, 17 of 24 subjects were recruited into the IB trial and received one booster dose (2 mg/0.5 ml) IM approximately 300 d after the first vaccination dose to which they were randomized in the first phase of the trial. All safety endpoints were met and all subjects tolerated CryJ2-LAMP vaccinations well. At the end of the IA trial, 10 out of 12 JRC sensitive and 6 out of 11 MC sensitive subjects experienced skin test negative conversion, possibly related to the CryJ2-LAMP vaccinations. Collectively, these data suggested that the CryJ2-LAMP DNA vaccine is safe and may be immunologically effective in treating JRC induced allergy.

Development of LAMP-based vaccine for cashew allergy immunotherapy

Tree nut allergy is the second most common triggers of anaphylaxis behind peanut in children and adults. Proactive therapies to decrease reaction severity are currently not available. Here, we utilized Lysosomal-associated membrane protein-1 (LAMP-1) as a targeting signal to make novel DNA vaccines against three major cashew allergens (Ana O1, Ana O2, Ana O3). Briefly, the chimeric constructs encoding the DNA sequences of Ana O1 or Ana O2 or Ana O3 or multivalent plasmid fused to LAMP-1 were synthesized and administrated to BALB/c mice through a needle-free delivery method (Biojector). By ELISA analysis, it showed that LAMP-Ana O 1/Ana O 2/Ana O 3 immunized mice produced high titers of IgG2a and moderate titers of IgG1 antibodies against each antigen. In contrast, IgE response was reduced in the vaccine immunized mice. Moreover, induction of IFN-γ and reduction of allergen-stimulated Th2 cytokine IL-4 were observed in vitro in splenocyte cells of LAMP-Ana O1/Ana O2/Ana O 3 treated mice after antigen stimulation, suggesting a predominant Th1 type immune response was elicited via DNA immunization. To further explore the therapeutic effect of this vaccine, we pre-sensitized the C3H/HeJ mice by oral gavage of protein of cashew extracts, and then immunized the mice with either single LAMP-Ana O plasmids or multivalent plasmid. LAMP-Ana O 1/Ana O 2/Ana O 3 treated mice exhibited strong IgG2a response and decreased IgE level, while control LAMP-vector treated mice demonstrated low IgG2a titer and higher IgE level accompanied by elevation of plasma histamine and IL-4 producing basophils in the blood. These results indicate that immunotherapy with LAMP-Ana O1/Ana O 2/Ana O 3 is effective, and may be a potential approach for treating cashew allergy.

CryJ-LAMP DNA Vaccines for Japanese Red Cedar Allergy Induce Robust Th1-Type Immune Responses in Murine Model

Allergies caused by Japanese Red Cedar (JRC) pollen affect up to a third of Japanese people, necessitating development of an effective therapeutic. We utilized the lysosomal targeting property of lysosomal-associated membrane protein-1 (LAMP-1) to make DNA vaccines that encode LAMP-1 and the sequences of immunodominant allergen CryJ1 or CryJ2 from the JRC pollen. This novel strategy is designed to skew the CD4 T cell responses to the target allergens towards a nonallergenic Th1 response. CryJ1-LAMP and CryJ2-LAMP were administrated to BALB/c mice and antigen-specific Th1-type IgG2a and Th2-type IgG1 antibodies, as well as IgE antibodies, were assayed longitudinally. We also isolated different T cell populations from immunized mice and adoptively transferred them into naïve mice followed by CryJ1/CryJ2 protein boosts. We demonstrated that CryJ-LAMP immunized mice produce high levels of IFN-γ and anti-CryJ1 or anti-CryJ2 IgG2a antibodies and low levels of IgE antibodies, suggesting that a Th1 response was induced. In addition, we found that CD4(+) T cells are the immunological effectors of DNA vaccination in this allergy model. Together, our results suggest the CryJ-LAMP Vaccine has a potential as an effective therapeutic for JRC induced allergy by skewing Th1/Th2 responses.