Autologous DCautologous dendritic cell
We evaluated the capacity of autologous DC and HEK293 cells transfected with relevant HLA alleles to function as T cell targets in Elispot assays upon transfection with tumor antigen encoding plasmids. Due to strong background from the autologous DC we decided that HEK293 transfected with one HLA-allele at a time plus simultaneously transfected with up to 5 tumor antiges would be optimal to screen for antigen specificity in the patients T cells. However, during a second T cell culture to expand large numbers of T cells for this screening procedure a drastic expansion of regulatory T cells was observed. Since no sufficient number of T cells could be expanded the screening was not performed. The reason for the altered phenotype/function of the expanded T cells from the second bleeding of this patient is currently not known.