In Vivo Targeting of Antigens to Maturing Dendritic Cells via the DEC-205 Receptor Improves T Cell Vaccination

Abstract

The prevention and treatment of prevalent infectious diseases and tumors should benefit from improvements in the induction of antigen-specific T cell immunity. To assess the potential of antigen targeting to dendritic cells to improve immunity, we incorporated ovalbumin protein into a monoclonal antibody to the DEC-205 receptor, an endocytic receptor that is abundant on these cells in lymphoid tissues. Simultaneously, we injected agonistic α-CD40 antibody to mature the dendritic cells. We found that a single low dose of antibody-conjugated ovalbumin initiated immunity from the naive CD4+ and CD8+ T cell repertoire. Unexpectedly, the αDEC-205 antigen conjugates, given s.c., targeted to dendritic cells systemically and for long periods, and ovalbumin peptide was presented on MHC class I for 2 weeks. This was associated with stronger CD8+ T cell–mediated immunity relative to other forms of antigen delivery, even when the latter was given at a thousand times higher doses. In parallel, the mice showed enhanced resistance to an established rapidly growing tumor and to viral infection at a mucosal site. By better harnessing the immunizing functions of maturing dendritic cells, antibody-mediated antigen targeting via the DEC-205 receptor increases the efficiency of vaccination for T cell immunity, including systemic and mucosal resistance in disease models.

Layer-by-Layer-Assembled Multilayer Films for Transcutaneous Drug and Vaccine Delivery

“…19,22,38 As a model protein cargo, we examined the assembly of multilayers containing ovalbumin (ova), a 45 KDa globular protein routinely used as a model vaccine antigen. [39][40][41] We first prepared PEM films by alternating adsorption of Poly-1 and ova from aqueous buffers onto glass slides, utilizing electrostatic interactions between the protein and polymer to mediate assembly and monitoring protein incorporation via the absorbance of fluorophore-conjugated ova. Based on the pI of ova (~4.6) and the pK a of Poly-1 (between 4.5 -8), we tested film assembly at pH 5 -7, varying the pH of both Poly-1 and ova adsorption solutions ( Figure S2).…”

“…[42][43][44] When dried as-assembled (Poly-1/ova) n PEM films on glass were rehydrated in phosphatebuffered saline (PBS, pH 7.4), films prepared across all deposition conditions exhibited rapid protein release, as illustrated in Figure 1c. Characterization of (Poly-1/ova) 40 film thickness vs. time following rehydration revealed rapid dissolution of the films coinciding with protein release. These films fall apart significantly more rapidly than others assembled with other proteins or biopolymers 19,21 , and also greatly exceed the rate of polyaminoester hydrolysis anticipated for Poly 1.…”

“…We next tested whether ova protein assembled into Poly-1 LbL films, dried, and then rehydrated and released into buffer remained intact and unaggregated by running both nonreducing SDS-PAGE ( Figure S3) and native PAGE on supernatants taken from (Poly-1/ ova) 40 films assembled at different pHs, dried, and then rehydrated in PBS for 30 min. As seen in Figure 1e, almost all of the ova released from poly-1 films existed as monomeric protein running at the same position as unmanipulated control ova solutions in PAGE gels, indicating that the structural integrity of ova was preserved during both integration into and subsequent release out of the films.…”

‘Survival gene’ Bcl-xl potentiates DNA-raised antitumor immunity

“…4 Recent investigations have been focused on modifying tumor antigens in order to target DCs for efficiently inducing immune responses in vivo. [5][6][7] Among molecules used to modify tumor antigens, heat shock protein 70 (hsp70) promotes DC activation and antigen presentation. 8,9 Molecules such as murine b-defensin2, human IgG-Fc and aDEC-205 have been reported to target antigens to DCs.…”

“…8,9 Molecules such as murine b-defensin2, human IgG-Fc and aDEC-205 have been reported to target antigens to DCs. [5][6][7] Hsp70 may be another ideal molecule for fusion to tumor antigens for developing an effective tumor vaccine. Hsp70 has been fused to foreign antigens such as viral E7 or rat Her2/Neu to enhance the potency of DNA vaccines in murine tumor models.…”