Fusion to the Lysosome Targeting Signal of the Invariant Chain Alters the Processing and Enhances the Immunogenicity of HIV-1 Reverse Transcriptase.
Intracellular processing of the antigen encoded by a DNA vaccine is one of the key steps in generating an immune response. Immunization with DNA constructs targeted to the endosomal-lysosomal compartments and to the MHC class II pathway can elicit a strong immune response. Herein, the weakly immunogenic reverse transcriptase of HIV-1 was fused to the minimal lysosomal targeting motif of the human MHC class II invariant chain. The motif fused to the N-terminus shifted the enzyme intracellular localization and accelerated its degradation. Degradation of the chimeric protein occurred predominantly in the lysosomal compartment. BALB/c mice immunized with the plasmid encoding the chimeric protein demonstrated an enhanced immune response, in the form of an increased antigen-specific production of Th1 cytokines, INF-γ and IL-2, by mouse splenocytes. Moreover, the majority of the splenocytes secreted both cytokines; i.e., were polyfunctional. These findings suggest that retargeting of the antigen to the lysosomes enhances the immune response to DNA vaccine candidates with low intrinsic immunogenicity.
Engelhardt Institute of Molecular Biology Russian Academy of Sciences, Vaviolva str., 32, 119991, Moscow, Russia ; D.I. Ivanovsky Institute of Virology, Ministry of Health of the Russian Federation, 123098, Moscow, Russia.
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Starodubova
D.I. Ivanovsky Institute of Virology, Ministry of Health of the Russian Federation, 123098, Moscow, Russia ; Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, 17177, Stockholm, Sweden.
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Isaguliants
Engelhardt Institute of Molecular Biology Russian Academy of Sciences, Vaviolva str., 32, 119991, Moscow, Russia.
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Kuzmenko
Engelhardt Institute of Molecular Biology Russian Academy of Sciences, Vaviolva str., 32, 119991, Moscow, Russia.
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Latanova
Engelhardt Institute of Molecular Biology Russian Academy of Sciences, Vaviolva str., 32, 119991, Moscow, Russia ; D.I. Ivanovsky Institute of Virology, Ministry of Health of the Russian Federation, 123098, Moscow, Russia.
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Krotova
Engelhardt Institute of Molecular Biology Russian Academy of Sciences, Vaviolva str., 32, 119991, Moscow, Russia.
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Karpov
DNA immunization; T-helper immune response; antigen processing; invariant chain; reverse transcriptase