Delivery of antigen using a novel mannosylated dendrimer potentiates immunogenicity in vitro and in vivo

Abstract

Antigen mannosylation has been shown to be an effective approach to potentiate antigen immunogenicity, due to the enhanced antigen uptake and presentation by APC. To overcome disadvantages associated with conventional methods used to mannosylate antigens, we have developed a novel mannose-based antigen delivery system that utilizes a polyamidoamine (PAMAM) dendrimer. It is demonstrated that mannosylated dendrimer ovalbumin (MDO) is a potent immune inducer. With a strong binding avidity to DC, MDO potently induced OVA-specific T cell response in vitro. It was found that the immunogenicity of MDO was due not only to enhanced antigen presentation, but also to induction of DC maturation. Mice immunized with MDO generated strong OVA-specific CD4 + /CD8 + T cell and antibody responses. MDO also targeted lymph node DC to crosspresent OVA, leading to OTI CD8 + T cell proliferation. Moreover, upon challenge with B16-OVA tumor cells, tumors in mice pre-immunized with MDO either did not grow or displayed a much more delayed onset, and had slower kinetics of growth than those of OVA-immunized mice. This mannose-based antigen delivery system was applied here for the first time to the immunization study. With several advantages and exceptional adjuvanticity, we propose mannosylated dendrimer as a potential vaccine carrier.

The Adjuvanticity of a Mannosylated Antigen Reveals TLR4 Functionality Essential for Subset Specialization and Functional Maturation of Mouse Dendritic Cells

“…MDO induces Ag presentation and DC maturation only in the presence of competent TLR4, while MDO internalization can be mediated by receptors including C-type lectins (18). MDO fails to elicit morphological/phenotypic maturation of C3H/HeJ DCs, in which no lysosomal localization is observed, given that it is bound and internalized at levels equivalent to wildtype C3H/He DCs.…”

“…Its immunogenicity was demonstrated by the strong OVA-specific immune responses induced in vitro and in vivo and by its efficacy in *Immunology and Vaccine Laboratory, Burnet Institute, Melbourne, Australia; induction of tumor protection in MDO-immunized mice (18). In the present study, using MDO as a PAMP-associated Ag, we further investigate its adjuvanticity in two heterogeneous DC populations, bone marrow DCs (BMDCs) composed of CD24 high and CD11b high subsets and fms-like tyrosine kinase 3 ligand (Flt3-L) DCs, which contain CD24 high , CD11b high , and B220 ϩ DCs (functional equivalents of mouse CD8 ϩ , CD8 Ϫ , and plasmacytoid subsets in vivo) (15,19).…”

“…Following this protocol, the final OVA product contained an undetectable level of LPS (Ͻ0.06 E.U./ml (0.01 ng/ml)) (EML). To synthesize MDO (18), mannosylated dendrimer (MD) was prepared. Eighty-four microliters of ␣-D -mannopyranosylphenyl isothiocyanate (Sigma-Aldrich) in DMSO (31.33 mg/ml) was slowly added into a solution containing 44 l of 10% (w/v in methanol) generation 4 PAMAM dendrimer (Dendritic Nanotechnologies) and 372 l of 0.2 M sodium bicarbonate buffer (pH 9.0).…”

Materials engineering for immunomodulation

“…Thus, the number of end groups on the dendrimer doubles with each serial step. As well-characterized display systems of well-defined and controllable size, these materials have great potential as vaccine platforms 38 .…”

Processing and presentation of (pro)‐insulin in the MHC class II pathway: the generation of antigen‐based immunomodulators in the context of type 1 diabetes mellitus

“…In addition to protease resistance being beneficial for effective APL, an improvement in APL uptake can potentially reduce the need for APL overload. Antigen uptake by DC via the mannose receptor is improved by mannosylation of antigens [115][116][117], and Agnes et al demonstrated improved APL uptake and a 1000-fold selective increase in APL internalization into the endocytic compartments by generating bis-mannosylated APL [118].…”