DNA Vaccine Plus Protein Vaccine Offers Tumor Protection.(Brief Article)

2001 APR 25 - (NewsRx.com & NewsRx.net) --

by N.R. Saltmarsh, staff medical writer - Combining a DNA vaccine with a protein vaccine against renal cell carcinoma is an effective strategy against tumor growth, say researchers working in Germany.

They sought to overcome the lack of effectiveness seen with many cancer vaccines by testing several protocols in mice.

"Since vaccination protocols are quite variable, we used the murine renal cell carcinoma line RENCA transfected with the lacZ gene (RENCA-(beta)-gal) to compare the efficacy of two different vaccination strategies or their combination and to elaborate on the underlying mechanisms," reported M. Zoller and colleagues.

They vaccinated BALB/c mice with either naked lacZ DNA, attenuated Salmonella typhimurium transformed with lacZ DNA, dendritic cells (DCs) loaded with the (beta)-galactosidase protein, or both DNA and protein.

"Although all regimens led to a prolongation of survival time, oral vaccination with transfected S. typhimurium followed by IV transfer of protein-loaded DC provided the optimal schedule," noted Zoller et al.

Fifty percent of mice given both the DNA and protein vaccines remained tumor-free after challenge with 10 times the lethal tumor dose of RENCA-(beta)-gal, they said ("Prophylactic tumor vaccination: Comparison of effector mechanisms initiated by protein versus DNA vaccination," Journal of Immunology, 2001;166(5):3440-3450).