Secretory Heat Shock Protein - gp96-Ig Chaperoned her-2/New Vaccines
Abstract
Three pertinent novel observations were made in this grant period that have tar reaching implications: First, using tumor cells that secrete a genetically engineered form of a heat shock protein, gp96-Ig, we showed that CD8 cells expanded and generated specific memory in vivo without the need for CD4 help. We have now analyzed this observation quantitatively by adoptive transfer of ovalbumin-TCR transgenic cells (OT1) into syngeneic mice as indicator cells in vivo and the use of EG7-gp96-Ig, a tumor secreting gp96Ig and containing ovalbumin as surrogate antigen. Using kb.tetramer assays, an expansion of OT1 is observed from an initial frequency of 0.5% to over 50% of all CD8 cells following primary injection and one boost with gp96Ig secreting. but not wild type EG7. Gp96Ig was found to directly activate dendritic cells without CD4 help. Second, this dramatic expansion of OT1 is seen in wild type mice, but it is completely abrogated in perforin deficient mice (PKO) and in perforin/Fas- ligand double deficient mice. Fas-ligand single deficient mice show normal expansion. This observation defines a novel role for perforin in CD8 activation and expansion via heat shock protein gp96 and its chaperoned peptides. Third, the dramatic expansion of cognate CD8 CTL is preceded by an equally dramatic expansion of NK cells that is also dependent on the presence of perforin. In addition to the novelty and unexpected nature of these observations stimulating new research approaches, the data provide a firm basis for future clinical trials in several tumors, including breast tumors, using gp96-Ig based vaccines.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 2001
- Accession Number
- ADA400054
Entities
People
- Eckhard Podack
Organizations
- University of Miami