Genetic modulation of tumor antigen presentation.

An effective cancer-cell vaccine is created by expressing major-histocompatibility-complex (MHC) class II molecules without the invariant chain protein (Ii) that normally blocks the antigenic-peptide-binding site of MHC class II molecules at their synthesis in the endoplasmic reticulum. Such tumor-cell constructs are created either by the transfer of genes for MHC class IIalpha and beta chains, or by the induction of MHC class II molecules and Ii protein with a transacting factor, followed by Ii suppression using antisense methods. Preclinical validation of this approach is reviewed with the goal of using this immunotherapy for metastatic human cancers.