Article

New developments in dendritic cell-based vaccinations: RNA translated into clinics.

Department of Internal Medicine II, Division of Hematology, Immunology, and Oncology, University of Tübingen, Otfried-Müller-Str. 10, 72076, Tübingen, Germany.
Cancer Immunology and Immunotherapy (impact factor: 3.7). 07/2005; 54(6):517-25. DOI:10.1007/s00262-004-0605-x pp.517-25
Source: PubMed

ABSTRACT Dendritic cells (DCs) are the most powerful antigen-presenting cells that induce and maintain primary immune responses in vitro and in vivo. The development of protocols for the ex vivo generation of DCs provided a rationale for designing and developing DC-based vaccination studies for the treatment of infectious and malignant diseases. Recently, it was shown that DCs transfected with ribonucleic acid (RNA) coding for a tumour-associated antigen or whole tumour RNA are able to induce potent antigen and tumour-specific T-cell responses directed against multiple epitopes. The first RNA-transfected-DC-based clinical studies have shown that this form of vaccination is feasible and safe. In some cases, clinical responses were observed, but the preliminary data require further extensive investigations that should address the technical and biological problems of manipulating human DCs, as well as the development of standardised protocols and definitions of clinical settings.

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    Article: Ectopic expression of a truncated CD40L protein from synthetic post-transcriptionally capped RNA in dendritic cells induces high levels of IL-12 secretion.
    Irina Y Tcherepanova, Melissa D Adams, Xiaorong Feng, Atsushi Hinohara, Joe Horvatinovich, David Calderhead, Don Healey, Charles A Nicolette
    [show abstract] [hide abstract]
    ABSTRACT: RNA transfection into dendritic cells (DCs) is widely used to achieve antigen expression as well as to modify DC properties. CD40L is expressed by activated T cells and interacts with CD40 receptors expressed on the surface of the DCs leading to Th1 polarization. Previous studies demonstrated that ectopic CD40L expression via DNA transfection into DCs can activate the CD40 receptor signal transduction cascade. In contrast to previous reports, this study demonstrates that the same effect can be achieved when RNA encoding CD40L is electroporated into DCs as evidenced by secretion of IL-12. To achieve higher levels of IL-12 secretion, a systematic approach involving modification of coding and noncoding regions was implemented to optimize protein expression in the DCs for the purpose of increasing IL-12 secretion. Site-directed mutagenesis of each of the first five in-frame methionine codons in the CD40L coding sequence demonstrated that DCs expressing a truncated CD40L protein initiated from the second methionine codon secreted the highest levels of IL-12. In addition, a post-transcriptional method of capping was utilized for final modification of the CD40L RNA. This method enzymatically creates a type I cap structure identical to that found in most eukaryotic mRNAs, in contrast to the type 0 cap incorporated using the conventional co-transcriptional capping reaction. The combination of knocking out the first initiation methionine and post-transcriptional capping of the CD40L RNA allowed for approximately a one log increase in IL-12 levels by the transfected DCs. We believe this is a first report describing improved protein expression of post-transcriptionally capped RNA in DCs. The post-transcriptional capping which allows generation of a type I cap may have broad utility for optimization of protein expression from RNA in DCs and other cell types.
    BMC Molecular Biology 11/2008; 9:90. · 2.86 Impact Factor
Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.

Keywords

biological problems
 
cases
 
DCs
 
DCs transfected
 
Dendritic cells
 
ex vivo generation
 
extensive investigations
 
first RNA-transfected-DC-based clinical studies
 
induce potent antigen
 
malignant diseases
 
manipulating human DCs
 
multiple epitopes
 
powerful antigen-presenting cells
 
preliminary data
 
primary immune responses
 
RNA
 
standardised protocols
 
technical
 
tumour-associated antigen
 
whole tumour RNA
 

Frank Grünebach