Disclosed is a specific regulator of Ii protein expression or immunoregulatoryfunction. Specifically disclosed are several forms of the specific regulatorof Ii, including those which function through the formation of a duplexmolecule with an RNA molecule encoding mammalian Ii protein to inhibit Iiprotein synthesis at the translation level. This class includes copolymerscomprised of nucleotide bases which hybridize specifically to the RNA moleculeencoding mammalian Ii protein, and also expressible reverse gene constructs.In other aspects, the disclosure relates to MHC class II-positive antigenpresenting cells containing a specific regulator of Ii expression. Such cellsare useful, for example, in the display of autodeterminant peptides inassociation with MHC class II proteins. Compositions of the invention findapplication in methods for treating diseases, for example malignancies andautoimmune disorders, in a patient by enhancing immunological attack onundesired cells. An additional application is the isolation of autodeterminantpeptides from a cell.
