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Innovative DNA vaccine to break immune tolerance against tumor self-antigen
Tae Heung Kang1, Chih-Ping Mao, Victor La
1Department of Pathology, Johns Hopkins Medical Institutions, Baltimore, MD 21231, USA.
Abstract:
Vaccination is, in theory, a safe and effective approach for controlling disseminated or metastatic cancer due to the specificity of the mammalian immune system, yet its success in the clinic has been hampered thus far by the problem of immune tolerance to tumor self-antigen. Here we describe a DNA vaccination strategy that is able to control cancer by overcoming immune tolerance to tumor self-antigen. We engineered a DNA construct encoding a dimeric form of a secreted single-chain trimer of major histocompatibility complex class I heavy chain, β2-microglobulin, and peptide antigen linked to immunoglobulin G (SCT-Ag/IgG). The chimeric protein was able to bind to antigen-specific CD8(+) T cells with nearly 100% efficiency and strongly induce their activation and proliferation. In addition, the chimeric protein was able to coat professional antigen-presenting cells through the F(c) receptor to activate antigen-specific CD8(+) T cells. Furthermore, intradermal vaccination with DNA-encoding SCT-Ag/IgG could generate significant numbers of cytotoxic effector T cells against tumor self-antigen and leads to successful therapeutic outcomes in a preclinical model of metastatic melanoma. Our data suggest that the DNA vaccine strategy described in the current study is able to break immune tolerance against endogenous antigen from melanoma and result in potent therapeutic antitumor effects. Such strategy may be used in other antigenic systems for the control of infections and/or cancers.
Insights
This study introduces a novel DNA vaccine strategy that overcomes immune tolerance to cancer self-antigens. The engineered vaccine effectively activates T cells, leading to successful therapeutic outcomes in preclinical melanoma models.
Area of Science:
- Immunology
- Oncology
- Vaccine Development
Background:
- Cancer vaccination faces challenges due to immune tolerance to tumor self-antigens.
- Developing effective cancer immunotherapies requires overcoming this immune evasion.
Purpose of the Study:
- To describe a DNA vaccination strategy capable of overcoming immune tolerance to tumor self-antigen.
- To evaluate the efficacy of a novel DNA vaccine in a preclinical cancer model.
Main Methods:
- Engineered a DNA construct encoding a chimeric protein (SCT-Ag/IgG) comprising MHC class I heavy chain, β2-microglobulin, and peptide antigen linked to IgG.
- Assessed the chimeric protein's ability to bind and activate antigen-specific CD8(+) T cells.
- Investigated the coating of antigen-presenting cells and subsequent T cell activation.
- Performed intradermal vaccination in a preclinical model of metastatic melanoma.
Main Results:
- The chimeric protein efficiently bound and activated antigen-specific CD8(+) T cells.
- Antigen-presenting cells coated with the chimeric protein effectively activated T cells.
- DNA vaccination generated significant cytotoxic effector T cells against tumor self-antigen.
- Achieved successful therapeutic outcomes in a preclinical melanoma model.
Conclusions:
- The described DNA vaccine strategy breaks immune tolerance to melanoma-associated antigens.
- This approach demonstrates potent therapeutic antitumor effects.
- The strategy holds potential for controlling other cancers and infections.
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