*2.3. Chicken Complement Inhibitor*

A chimeric version of the oligomerization domain from the chicken complement inhibitor (C4bp) was used to produce an oligomeric form of vaccine antigens [35,83]. This protein, termed IMX313, forms a heptameric structure of the vaccine protein. This has been used to develop DNA vaccines for tuberculosis, malaria and HIV to enhance humoral and/or cellular responses [35,36,84]. Vaccination with a DNA vaccine encoding secreted HIV Tat (TPA-Tat IMX313) induced higher humoral and cellular responses and improved protection against EcoHIV challenge in mice [36]. A phase I clinical trial of tuberculosis vaccine MVA85A-IMX313 evaluated the vaccine to be safe and immunogenic, but cellular (Ag85A-specific IFN- ᎇ) and humoral (MVA-specific IgG) responses were not significant [85]. Thus, the ability of such an adjuvant to enhance immunogenicity of DNA vaccines in humans is still debated.
