However, CpG treatment leads to enhanced cross presentation from the DC and this was also dependent on the ROS production. When we allowed Salmonella infection in the CpG treated DCs, the same trend was maintained. Salmonella could not alter the enhanced antigen presentation and thus we hypothesize that like H-antigen any other Salmonella antigen could also be cross-presented in a better way by CpG induction. This idea is further supported by the animal experiments performed with the CpG treated DCs. The injected DCs could reduce the bacterial load from infected mice from both liver and spleen. This might be due to enhanced antigen presentation and killing of the bacteria by the anti-Salmonella T cells. To be precise, this paper deals with two novel findings. In one hand, CpG treatment leads to killing of Salmonella in a ROS dependent manner. On the other, CpG induction leads to better antigen presentation from the Salmonella infected DCs which is also dependent on ROS. These two findings might be related in a way as enhanced killing of the pathogen might allow better presentation as well which is again supported by the in vivo data. In conclusion, our finding is the first to indicate that activating host innate immune receptor TLR-9 can improve Salmonella killing and antigen presentation by DCs. We speculate that our results will have important implications in the development of novel Salmonella vaccines utilizing CpG as an adjuvant. Future studies should focus on the exact mechanism by which ROS enhances the antigen presentation in the Salmonella infected DCs. Immune cells are characterized by specific morphologies and functions, which can be used to identify different immune cell types. This is illustrated by the use of flow cytometry to identify immune cell populations based on the recognition of increasing numbers of membrane antigens by specific antibodies. This method has been widely applied in the fields of immunology and hematology. The development of systems biology approaches has enabled cell MLN4924 subsets to be identified through their characteristic transcriptional signatures. For example, it has been recently reported that circulating lymphocytes and polymorphonuclear cells exhibit gene expression signatures reflecting the enrichment of genes encoding specific surface proteins that can be used as biomarkers for estimating the abundance of these cell types within complex tissues. This approach enables discrimination between cells in the same lineage but at different stages and between cells that have differentiated, such as the differentiation of human monocytes into macrophages or dendritic cells. However, changes in mRNA levels do not necessarily reflect the altered expression of proteins.