Autologous dendritic cells pulsed with necrotic tumor lysate generated in vitro B-CLL-specific HLA class I restricted CTL responses

06-26-2006

According to a study from Canada, "New approaches in the treatment of chronic B lymphocytic leukemia (B-CLL) have led to improved clinical response rates. In this setting there is a need to evaluate novel therapeutic approaches that aim to eradicate minimal residual B-CLL cells following an initial favorable response. The use of tumor lysate-pulsed dendritic cells (DC) represents a potentially important development in the field of cancer vaccination. B-CLL is ideally suited for DC-based vaccination since tumor cells are readily available (peripheral blood) and both known (tumor idiotype) and unknown antigens can be exploited to stimulate immune responses."

"In the current study, we have evaluated the ability to stimulate in vitro autologous immune reactivity against target B-CLL cells using autologous DCs pulsed with B-CLL tumor lysate," said Kalathil Suresh and colleagues at McMaster University. "Enhanced specific T cell IFN-gamma expression was detected in 9 of 14 patients evaluated. These responses were specific with increased levels of IFN-gamma mRNA measurable in T-cells stimulated with NC-DCs and not unpulsed DCs or DCs pulsed with normal B cell lysate. CTLs demonstrating increased levels of IFN-gamma mRNA also lysed autologous B-CLL targets cells in an MHC class 1-restricted manner by 51Cr release assay."

"Priming target leukemic cells with CD40 ligand and IL-4 enhanced CTL killing," reported the investigators. "The effector CTL displayed negligible toxicity against NK susceptible target cells K-562 and spared CD19+CD5- normal B cells in cytotoxicity assays. The specificity of the CTL response was confirmed by blocking HLA class I molecules and cold target inhibition assays."

Suresh and associates published their study in Leukemia and Lymphoma (Generation of in vitro B-CLL specific HLA class I restricted CTL responses using autologous dendritic cells pulsed with necrotic tumor lysate. Leuk Lymphoma, 2006;47(2):297-306).

For more information, contact Ronan Foley, Centre for Gene Therapeutics, Department of Pathology and Molecular Medicine, McMaster University, 2nd Floor Laboratory, 711 Concession Street, Hamilton, ON L8V 1C3, Canada. foleyr@hhsc.ca.

This article was prepared by Cancer Vaccine Week editors from staff and other reports. Copyright 2006, Cancer Vaccine Week via NewsRx.com.