Heat Shock Protein Enhances Suicidal DNA Vaccine Potency.(Brief Article)

2001 MAY 16 - (NewsRx.com & NewsRx.net) --

by N.R. Saltmarsh, staff medical writer - The addition of Mycobacterium tuberculosis heat shock protein 70 (Hsp70) to suicide gene vectors may boost vaccine effectiveness, say researchers working in the United States.

Because suicide gene vectors eventually cause lysis of transfected cells, their use overcomes some of the drawbacks of other kinds of DNA vaccines. Specifically, they have the potential to integrate into the host genome and cell transformation, while retaining benefits such as stability and simplicity of delivery, noted K.F. Hsu and colleagues at Johns Hopkins University.

"To improve further the potency of suicidal DNA vaccines, we evaluated the effect of linking M. tuberculosis Hsp70 to human papillomavirus type 16 (HPV-16) E7 as a model antigen on antigen-specific immunity generated by a DNA-based Semliki Forest virus (SFV) RNA vector, pSCA1," reported Hsu and team.

Their suicidal E7/Hsp70 DNA vaccine generated higher E7-specific immune responses than a wild-type E7 vaccine in mice and, more important, improved the potency of a vaccine against established E7-expressing metastatic tumors, said Hsu and coworkers.

The anti-tumor effect was predominantly CD8-dependent ("Enhancement of suicidal DNA vaccine potency by linking ...