Multiple display of protein domains by means of a oligomeric scaffold through recombinant fusion and high affinity leucine zippers peptides

CRAIG PO; BERGUER PM; GOLDBAUM FA

Montevideo, Uruguay

Congreso; 6th International Conference of Biological Physics (ICBP), 5th Southern Cone Biophysics Congress and Biophysical Society of Argentina (SAB) 36th Annual Meeting; 2007

Oligomeric proteins are good immunogens. This behaviour is attributed to the highly repetitive array of epitopes that exist in this kind of antigens. Brucella Abortus Lumazine Sinthase (BLS) is a highly immunogenic decameric protein. In the past, BLS was successfully used as a carrier to enhance the immunogenicity of short peptides and small proteins fused to its N terminal. However, the folding and assembly of BLS fused to large and complex proteins is not always straightforward. In this work, we describe the coupling of a monomeric double stranded RNA binding domain (RBD3) to the structure of BLS through high affinity heterodimerizing leucine zippers peptides LEU1 and LEU2, fused to each protein. Mixing of LEU1-BLS and RBD3-LEU2 shields a properly folded and stable decameric ensemble of these proteins, as evidence by Light Scattering and CD measurements. Immunization of mice with RBD3-LEU2 produced no significant immunological response toward this antigen. By contrast, immunization with the RBD3-LEU2::LEU1-BLS ensemble produced a strong and specific immunological response against both BLS and RBD3, breaking the tolerance of mice to the RBD3 self antigen. Finally, these results demonstrates the potential of the BLS carrier approach to deliver small proteins to the immune system in a highly order array, preserving their natural conformation and enhancing their immunogenicity.