A new peptide construct Palm135-158-GGA-170-188(Acm) has been synthesized and investigated in a number of in vitro and in vivo test systems. The construct contains a virus specific T-helper epitope within the 170-188 sequence of VP1, in addition to the main antigenic 135-158 region of the foot-and-mouth disease viral VP1protein (strain A22). The construct has higher protective, antigenic, immunogenic and T-cell proliferative activity then the previously described shorter peptide Palm2135-159. The 170-188 part of the construct serves as a virus specific T-epitope, responsible for the enhanced immunogenic and protective activity of the construct.