Messenger RNA-Electroporated Dendritic Cells Presenting MAGE-A3 Simultaneously in HLA Class I and Class II Molecules

Abstract

An optimal anticancer vaccine probably requires the cooperation of both CD4+ Th cells and CD8+ CTLs. A promising tool in cancer immunotherapy is, therefore, the genetic modification of dendritic cells (DCs) by introducing the coding region of a tumor Ag, of which the antigenic peptides will be presented in both HLA class I and class II molecules. This can be achieved by linking the tumor Ag to the HLA class II-targeting sequence of an endosomal or lysosomal protein. In this study we compared the efficiency of the targeting signals of invariant chain, lysosome-associated membrane protein-1 (LAMP1) and DC-LAMP. Human DCs were electroporated before or after maturation with mRNA encoding unmodified enhanced green fluorescent protein (eGFP) or eGFP linked to various targeting signals. The lysosomal degradation inhibitor chloroquine was added, and eGFP expression was evaluated at different time points after electroporation. DCs were also electroporated with unmodified MAGE-A3 or MAGE-A3 linked to the targeting signals, and the presentation of MAGE-A3-derived epitopes in the context of HLA class I and class II molecules was investigated. Our data suggest that proteins linked to the different targeting signals are targeted to the lysosomes and are indeed presented in the context of HLA class I and class II molecules, but with different efficiencies. Proteins linked to the LAMP1 or DC-LAMP signal are more efficiently presented than proteins linked to the invariant chain-targeting signal. Furthermore, DCs electroporated after maturation are more efficient in Ag presentation than DCs electroporated before maturation.

mRNA-based cancer vaccine: prevention of B16 melanoma progression and metastasis by systemic injection of MART1 mRNA histidylated lipopolyplexes

“…The transfection of DCs with sig-MelanA-LAMP1, sig-MAGE-LAMP1 and sig-carcinoembryonic antigen (CEA)-LAMP1 mRNA encoding chimeric MART1, MAGE and CEA have been shown to promote induction of an antigen-specific CD4 þ T-cell response. [53][54][55] The vaccination of mice with DNA encoding sig-E7-LAMP1-16 have generated simultaneous CD4 þ and CD8 þ T-cell responses against the human papillomavirus. [56][57][58] Lastly, the injection of DCs transfected with the telomerase reverse transcriptase-LAMP1 mRNA has led to an enhancement of antigen-specific CD4 þ and CD8 þ T cells against metastatic prostate cancer in humans.…”

Dendritic cell preactivation impairs MHC class II presentation of vaccines and endogenous viral antigens

“…In the latter case, the TLR ligand may reach DCs that have not yet encountered the antigen, inducing their maturation and thus preventing their participation in antigen presentation. Finally, it is important to note that immunotherapeutic approaches (18) consisting of inoculation of DCs that are first induced to mature in vitro, and then transfected with nucleic acids encoding tumor antigens (43), might result in DCs presenting the antigens via MHC I but not via MHC II (44), although evidence to the contrary has been reported as well (45,46). Lack of induction of helper T cells might lead to poor induction of protective cytotoxic T lymphocyte immune responses (47) or even induce tolerance (48), so caution must be exerted when employing this strategy.…”

In vitro Induction of Myeloid Leukemia–Specific CD4 and CD8 T Cells by CD40 Ligand – Activated B Cells Gene Modified to Express Primary Granule Proteins

“…An alternative strategy would be to use gene-modified dendritic cell to present peptides from PGP protein to CD4 and CD8 T cells. Dendritic cells have the advantage of being the most reliable APC to generate cytotoxic T lymphocytes, and both dendritic-cell and B-cell APC can present peptides from transduced protein genes (32,33). Translational research to make one or other of these approaches applicable for the induction and adoptive transfer of leukemia-specific T cells in clinical trials is now required.…”