The present invention relates to a method for increasing the uptake, processing and class I presentation of a soluble antigen by an immature dendritic cells, comprising the steps of: a) obtaining a population comprising human immature dendritic cells； b) culturing the population immature dendritic cells in vitro in a cell culture medium supplemented with a agent that promotes Major-Histocompatability Complex - (MHC-) class I processing and a soluble antigen associated with a tumor cell for a time period sufficient for antigen uptake, processing and presentation, and until maturation of the immature dendritic cells in the population； c) separating the soluble tumor antigen and the agent that promotes MHC-class I processing from the mature tumor antigen presenting dendritic cells； and d) formulating the mature tumor antigen presenting dendritic cells for administration to a patient.
