Activated CD8+ T cells (T-CD8+) can directly recognize malignant cells
because processed fragments of tumour associated antigens (TAA), 8-10
amino acids in length and complexed with MHC class I molecules, are d
isplayed on tumour cell surfaces. Tumour cells have been genetically m
odified is a variety of ways ill efforts to enhance the immune recogni
tion of TAA. An alternative strategy is the expression of TAA in recom
binant or synthetic form. This has been made possible by the recent cl
oning of TAA recognized by T-CD8+. In this communication we review rec
ent work in our own laboratory on the expression of TAA as synthetic p
eptide, by ''naked'' plasmid DNA injected intramuscularly or transderm
ally, and by recombinant viruses including vaccinia (rVV), fowlpox (rF
V) and adenovirus (rAd). The expression of TAA in recombinant and synt
hetic forms allows increased control over the quantity, location, and
kinetics of TAA presentation and can result in powerful, Specific, ant
i-tumour immune responses.