Rabies DNA vaccine: No impact of MHC Class I and Class II targeting sequences on immune response and protection against lethal challenge

Abstract

Rabies is progressive fatal encephalitis. WHO estimates 55,000 rabies deaths and more than 10 million PEP every year world-wide. A variety of cell-culture derived vaccines are available for prophylaxis against rabies. However, their high cost restricts their usage in developing countries, where such cases are most often encountered. This is driving the quest for newer vaccine formulations; DNA vaccines being most promising amongst them. Here, we explored strategies of antigen trafficking to various cellular compartments aiming at improving both humoral and cellular immunity. These strategies include use of signal sequences namely Tissue Plasminogen Activator (TPA), Ubiquitin (UQ) and Lysosomal-Associated Membrane Protein-1 (LAMP-1). TPA, LAMP-1 and their combination were aimed at enhancing the CD4(+) T cell and antibody response. In contrast, the UQ tag was utilized for enhancing CD8(+) response. The potency of modified DNA vaccines assessed by total antibody response, antibody isotypes, cytokine profile, neutralizing antibody titer and protection conferred against in vivo challenge; was enhanced in comparison to native unmodified vaccine, but the response elicited did not pertain to the type of target sequence and the directed arm of immunity. Interestingly, the DNA vaccines that had been designed to generate different type of immune responses yielded in effect similar response. In conclusion, our data indicate that the directing target sequence is not the exclusive deciding factor for type and extent of immune response elicited and emphasizes on the antigen dependence of immune enhancement strategies.

Enhancement of immunogenicity and efficacy of a plasmid DNA rabies vaccine by nanoformulation with a fourth-generation amine-terminated poly(ether imine) dendrimer

“…This is in agreement with Kaur et al, who reported variation in protective efficacy despite similar magnitude of immune responses. 28 It is possible that cellular immune factors, in addition to RVNA, may also be involved in protection against intracerebral rabies virus challenge. The present study, however, did not evaluate the cellular immune responses to dendriplex vaccination.…”

Rabies Control and Treatment: From Prophylaxis to Strategies with Curative Potential

“…To improve DNA uptake, electroporation has been used and was shown to generate comparable or superior levels of immune responses [102,103]. To increase the immunogenicity and efficacy of DNA vaccines, several approaches have been conducted, including using chemical adjuvants [104,105], co-administrating plasmids expressing cytokines [106,107], modifying the targeted G protein [108,109], increasing the expression level of encoded proteins [94], co-inoculating with a traditional inactivated rabies vaccine [110], and optimizing DNA vaccine formulation, such as through targeted trafficking of a G protein to a lysosome supplemented with adjuvant Emulsigen-D [111,112]. These endeavors have significantly increased the immunogenicity and efficacy of DNA vaccines and extended their potential in preventing and controlling rabies.…”

Regulation of HIV-Gag Expression and Targeting to the Endolysosomal/Secretory Pathway by the Luminal Domain of Lysosomal-Associated Membrane Protein (LAMP-1) Enhance Gag-Specific Immune Response

“…In this regard, antigen targeting to different cellular processing compartments may improve its presentation by MHC I or MHC II molecules and enhance specific immune response [28][29][30][31][32]. In addition, the secretion of cellular proteins was reported to modulate the immunological responses.…”