title: Quality of tumor lysates used for pulsing dendritic cells is influenced by the method used to harvest adherent tumor cells.
abstract: BACKGROUND
  Lysates from tumor cells are reported to induce maturation of dendritic cells (DCs) and are used in clinical settings for DC-based vaccination against solid tumors. Nevertheless, the maturation inducing effect of tumor lysates on DCs is discussed controversially and the efficacy of tumor vaccines varies significantly.
  
  
  RESULTS
  Using three individual adherent colorectal tumor cell lines we also faced the difficulty to obtain consistent results regarding maturation inducing effect of tumor lysates on DCs. Therefore, we compared different methods to prepare tumor cell lysate and could demonstrate that trypsinizing as a method to harvest adherent tumor cells has a significant negative impact on biologic activity of tumor lysates. Specifically, we assessed induction of maturation markers CD40, CD80, and CD86 on DCs which were treated with differently prepared lysates.
  
  
  CONCLUSIONS
  Trypsinizing is a very common way of harvesting adherent cells from culture flasks. Our results shall call investigators' attention to the enzymatic activity of trypsin degrading some possibly important proteins on the surface of cultured cells. Specifically for DC-based vaccination against tumor antigens investigators should avoid trypsin.
authors: Institute of Transfusion Medicine, University of Ulm, Germany. r.lotfi@blutspende.de.
authors: Gloria Isabelle
authors: GI
authors: Herzog
authors: Ghasem
authors: G
authors: Solgi
authors: Denis S
authors: DS
authors: Wiegmann
authors: Christian
authors: C
authors: Nienhaus
authors: Hubert
authors: H
authors: Schrezenmeier
authors: Tatjana
authors: T
authors: Yildiz
authors: Ramin
authors: R
authors: Lotfi
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