Human dendritic cells pulsed with autologous Epstein-Barr virus transformed B-cell lymphoblastoid cell (BCL) lysate elicit a BCL specific MHC-Class II restricted T-cell response

Epstein Barr Virus (EBV) associated lymphoproliferative disorders (LPD) exp ress EBV latent antigens that are also expressed on normal B-cells transfor med with EBV. This could potentially be exploited to develop immunotherapeu tic strategies for LPD and other EBV associated malignancies. To this end w e investigated the capacity of human monocyte derived dendritic cells (DC) pulsed with lysate from autologous EBV transformed B-cell lymphoblastoid ce ll (BCL) lysate to elicit an in vitro antitumor response. BCL lysate pulsed DC generate BCL specific cytotoxic lymphocytes, as lymphocytes primed with such DCs induce cytolysis of autologous (> 60%) but not allogeneic BCL(<5% ). In addition, lymphocytes primed with BCL lysate pulsed DC secrete gamma -IFN (3176 pg/ml). Whereas gamma -IFN production was markedly reduced (> 99 %) when BCL specific T-cells were stimulated by BCL lysate pulsed DC in the presence of blocking antibodies to HLA-DR, DP and DQ, use of antibodies to MHC class-I resulted in only a minimal reduction in gamma -IFN production( 17%). These studies demonstrate that BCL lysate pulsed DC elicit a predomin antly BCL specific, MHC class-II restricted T cell response. This suggests that vaccination with autologous BCL lysate pulsed DC may represent a viabl e immunotherapeutic approach for the treatment of LPD.