Fusion to the Lysosome Targeting Signal of the Invariant Chain Alters the Processing and Enhances the Immunogenicity of HIV-1 Reverse Transcriptase

Abstract

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.

Medroxyprogesterone Acetate (MPA) Enhances HIV-1 Accumulation and Release in Primary Cervical Epithelial Cells by Inhibiting Lysosomal Activity

“…Taken together, our findings suggest that MPA enhances HIV intracellular accumulation and extracellular release by inhibiting lysosomal activity. Several studies have revealed the association of lysosomal activity with HIV-1 pathogenesis [ 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 ]. While these reports agree that inhibiting lysosomal activity would increase HIV-1 infectivity, whether lysosomal activity would affect viral release remains controversial.…”

Codon optimization and improved delivery/immunization regimen enhance the immune response against wild-type and drug-resistant HIV-1 reverse transcriptase, preserving its Th2-polarity

“…However, RT encoded by viral genes was only weakly immunogenic 40 , 45 . We attempted to enhance its immunogenicity by redirecting RT to alternative pathways of antigen processing through fusion to various retargeting signals 35 , 36 , 42 , 46 . A significant improvement in immunogenic performance was achieved only in the case of RT retargeting to the lysosome 46 .…”

“…We attempted to enhance its immunogenicity by redirecting RT to alternative pathways of antigen processing through fusion to various retargeting signals 35 , 36 , 42 , 46 . A significant improvement in immunogenic performance was achieved only in the case of RT retargeting to the lysosome 46 . We also tested whether RT can be made more immunogenic by expression optimization and artificial secretion, which we thought would help to overcome RT-induced oxidative stress, potentially toxic to the expressing cells 43 .…”

Design of genetic construction for creation DNA vaccine against porcine reproductive and respiratory syndrome

“…о. ), которая способствует направлению пептидов в лизосомы [12]. Предполагается, что присоединение этой сигнальной последовательности к антигенам, кодируемым ДНК-вакциной, позволит обеспечить эффективное взаимодействие с белками МНС II, усилив тем самым их презентацию соответствующим иммунокомпетентным клеткам.…”