| Cross-presentation, presentation of non-cell derived antigen via MHC class I molecules, is considered of paramount importance for various immunological responses such as peripheral tolerance and viral immunity. Dendritic cells (DCs) are essential for this process in vivo. In mice and men, several subsets of DCs have been identified. It has been postulated that in mice a particular subset, CD8alpha postive, is specialized in cross-presentation. However, the evidence for this involvement required purification and in vitro culturing of DCs, which has a profound influence on DC phenotype. To directly assess the involvement of DC subsets in cross-presentation in vivo without the need of ex-vivo manipulation, we will generate mice devoid of specific DC subsets and test the ability of cross-priming in these mice. To that end, we will knock out specific genes which are known to be involved in DC subset formation using a novel technique termed ?RNA interference?. First, we will verify gene suppression of targeted genes and accompanying phenotype of DCs in vitro. Next, we will generate so-called chimeric mice which have been engrafted with bonemarrow lacking specific subsets and asses cross-presentation potential of remaining DC subsets. |
