Induction of antigen specific CD4+T cell responses by invariant chain based DNA vaccines

In this report, the use of DNA vaccination to induce class II restricted an tigen specific proliferative responses was studied. To this end, a construc t encoding the invariant chain (Ii) was engineered in which the Class II as sociated invariant chain peptide (CLIP) sequence was replaced by an immunog enic epitope derived form Heat Shock Protein 60, HSP60 178-186. Transfectio n studies in vitro showed that this construct can be used to efficiently lo ad MHC class II molecules and present epitopes to MHC class II restricted a ntigen specific T cells. In addition, we showed that intradermal immunisati on of Lewis rats with these constructs induced antigen specific T cells in vivo. Therefore, our Ii-gene constructs can be used to immunise for defined CD4 + T cell epitope sequences. (C) 2001 Elsevier Science Ltd. All rights reserved.