Tobacco mosaic virus efficiently targets DC uptake, activation and antigen-specific T cell responses in vivo

Abstract

Over the past 20 years, dendritic cells (DCs) have been utilized to activate immune responses capable of eliminating cancer cells. Currently, ex vivo DC priming has been the mainstay of DC cancer immunotherapies. However, cell-based treatment modalities are inherently flawed due to a lack of standardization, specialized facilities and personnel, and cost. Therefore, direct modes of DC manipulation, circumventing the need for ex vivo culture, must be investigated. To facilitate the development of next-generation, in vivo targeted DC vaccines, we characterized the DC interaction and activation potential of the Tobacco Mosaic virus (TMV), a plant virus that enjoys a relative ease of production and the ability to deliver protein payloads via surface conjugation. In this study we show that TMV is readily taken up by mouse bone marrow-derived DCs, in vitro. Footpad injection of fluorophore-labeled TMV reveals preferential uptake by draining lymph node resident DCs in vivo. Uptake leads to activation, as measured by the upregulation of key DC surface markers. When peptide antigen-conjugated TMV is injected into the footpad of mice, DC-mediated uptake and activation leads to robust antigen-specific CD8+ T cell responses, as measured by antigen-specific tetramer analysis. Remarkably, TMV priming induced a greater magnitude T cell response than Adenovirus (Ad) priming. Finally, TMV is capable of boosting either Ad-induced or TMV-induced antigen-specific T cell responses, demonstrating that TMV, uniquely, does not induce neutralizing self-immunity. Overall, this study elucidates the in vivo DC delivery and activation properties of TMV, and indicates its potential as a vaccine vector in stand alone or prime-boost strategies.

Single-dose monomeric HA subunit vaccine generates full protection from influenza challenge

“…TMV can directly stimulate dendritic cell (DC) antigen uptake in vitro, 24 along with DC activation, migration of DCs to lymphoid organs and robust stimulation of antigen-specific B and T cells in vivo. 46 As clearly demonstrated in these studies, TMV also serves as an adjuvant to the conjugated subunit vaccine protein, which may have importance in geographic areas where cold-storage dependant adjuvants are impractical. Using TMV to deliver HA protein harnesses DC uptake and activation to stimulate effective antigen presentation, and influences the quality of the subsequent protective immune response.…”

Intranasal delivery of a protein subunit vaccine using a Tobacco Mosaic Virus platform protects against pneumonic plague

“…The similarities between the measured immune responses generated by IM vaccination with rLcrV and IN vaccination with lipLcrV-L. plantarum , implies that the differences in the protective effect between the two vaccines does not lie in either the antibodies or cytokines tested here, but in some as of yet unidentified factor(s) that contributed to protection from pneumonic plague. TMV has been previously demonstrated to enhance humoral and cell mediated immunity to subunit vaccines, enhancing antigen uptake and presentation by professional antigen presenting cells [21]. We hypothesize that direct uptake of the viral particle, albeit a recombinantly expressed plant pathogen, enhances the response to the associated subunit protein by simulate antiviral signaling.…”

“…However, parenteral administration of subunit vaccines induces variable protection in non-human primates, implying that they may not protect humans against pneumonic plague [7,14–17]. We have previously utilized TMV as a delivery platform to amplify cellular and humoral immune responses to subunit vaccines, inducing protection against mucosally administered pathogens, F. tularensis and Influenza A [21–24]. Therefore, we altered our protocol incorporating the use of a TMV platform for the IN delivery of a subunit vaccine consisting of rLcrV and rF1 proteins.…”

“…TMV is a plant virus that cannot infect animals cells, but has been shown to interact with and stimulate mammalian dendritic cells [21]. TMV-conjugate vaccines have demonstrated protection against challenge with Francisella tularensis [22], and Influenza H1N1 [23] and H5N1 [24].…”

Peer Review #3 of "Application of built-in adjuvants for epitope-based vaccines (v0.1)"

“…Manuscript to be reviewed viral RNA that is important for inducing cellular-mediated immunity (Banik et al, 2015). Kemnade et al demonstrated that TMV is capable of boosting TMV-induced antigen-specific T cell responses, but does not induce neutralizing self-immunity (Kemnade et al, 2014). In addition, since TMV is not a human pathogen, it is intrinsically secure (Liu et al, 2013).…”