DNA vaccine has been tested for protection against foot-and-mouth disease. However, the relatively low efficacy of DNA vaccine in inducing immune responses in large animals has restricted its practical use. Interleukin-1 plays an essential role in amplifying both the cellular and humoral immune responses to foreign antigens, and may therefore represent a good candidate as an adjuvant of DNA vaccines. Since the inflammatory activity of IL-I may restrict its application in DNA vaccine treatment, we explored the possibilities of augmenting immune responses without unwanted inflammatory effects using the IL-1beta fragment (amino acids (aa) 163-171), which is essential for IL-1 receptor-1 binding. The DNA fragment encoding the human IL-1beta fragment (aa 163-171) was fused to foot-and-mouth disease virus (FMDV) DNA vaccine, and injected into mice to analyse its immune response. Compared with control mice receiving FMDV DNA vaccine alone, significant increases in the FMDV-specific antibody response and also in T cell proliferation were observed in mice receiving IL-1beta (163-171)-FMDV. These results suggested that DNA fragment encoding IL-1beta 163-171 peptide might represent a good candidate for an adjuvant of FMDV DNA vaccine.