Vaccination with idiotypic protein or DNA failed to prolong dormancy in mice with BCL1 lymphoma

08-21-2006

According to scientists in the United States and England, "Immunization of mice with the idiotype (Id) immunoglobulin from the murine B cell lymphoma, BCL1, before inoculating tumor cells can induce tumor dormancy. In this model, file turner cells grow for a short period of time and then regress. The mice live for months or years with approximately one million turner cells in their spleens. Some mice relapse due to decreases in the anti-Id antibody titers or the development of initiations in the residual minor cells which render them refractory to negative signaling by the anti-Id antibody."

"In this study we determined whether we could eliminate the residual dormant cells by using a DNA vaccine against the Id or by immunomodulation of T-cell subsets in vivo," said Laurentiu M. Pop and collaborators at the University of Texas Southwestern Medical Center in the U.S. and Southampton University in England. "Our results demonstrate that dormancy can be maintained by further immunizations with either the BCL1 Id protein or DNA vaccine encoding its single-chain Fv fragment. We also found that a cytotoxic T-cell response was not induced by either in vivo administration of vaccine alone or by the vaccine plus interleukin-2."

The researchers noted, "In addition, the injection of anti-cytotoxic T-lymphocyte-associate antigen did not prolong dormancy. Finally, the in vivo administration of anti-CD25 to deplete regulatory T cells did not prolong dormancy."

"Dormancy in this model is dependent primarily upon anti-Id antibodies; our results suggest that other strategies to target residual dormant BCL1 cells are warranted. They also suggest that the elimination of dormant tumor may represent a greater challenge than the elimination of primary tumors," the authors concluded.

Pop and associates published their study in the Journal of Immunotherapy (Failure of vaccination with idiotypic protein or DNA, (+/- IL-2), the depletion of regulatory T cells, or the blockade of CTLA-4 to prolong dormancy in mice with BCL1 lymphoma. J Immunother, 2005;28(6):525-534).

For additional information, contact Ellen S. Vitetta, Cancer Immunobiology Center, University of Texas Southwestern Medical Center, 6000 Harry Hines Boulevard, NB9-210, Dallas, TX 75216-8576, USA.

Keywords: Dallas, Texas, United States, Lymphoma Vaccine, Cancer Vaccine, Vaccine Development, Vaccine Efficacy, DNA Vaccine, Immunology, Immunotherapy, Oncology, Proteomics.

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