A novel strategy for converting recombinant viral protein into high immunogenic antigen.

Interleukin 2 (IL-2) is a lymphokine promoting immune response and therefore has been investigated as an immunological adjuvant. In order to enhance the immunogenicity of recombinant viral protein, herpes simplex virus type 1 (HSV-1) glycoprotein D (gD), we genetically created a fusion protein consisting of gD and human IL-2. The fusion protein, without any other adjuvants, induced high antibody responses and cell-mediated immunity to HSV-1 in mice. Mice immunized with the fusion protein were protected against HSV-1 infection. The results indicate that IL-2-fusing can provide a means for converting a weak immunogenic protein into a high immunogenic antigen, and the strategy would be widely applicable to the other antigens for pathogens.