Complexes of streptavidin-fused antigens with biotinylated antibodies targeting receptors on dendritic cell surface: a novel tool for induction of specific T-cell immune responses.

The choice of tools that enable efficient targeting of exogenous antigens (Ag) for processing and presentation by professional Ag-presenting cells (APC) remains limited. This represents, indeed, a bottleneck in development of vaccines inducing specific T-cell responses. Here, we describe a novel strategy of Ag delivery into APCs. The Ag of choice is fused to the N- or C-terminus of streptavidin (SA) and tetrameric Ag-SA or SA-Ag fusion proteins are produced in E. coli and purified by 2-Iminobiotin-Agarose affinity chromatography. Alternatively, Ag-SA proteins are purified from urea extracts of E. coli inclusion bodies and refolded in vitro into functional tetramers. Complexes with biotinylated antibodies targeting cell surface receptors are formed and used to deliver the Ags of choice for processing and presentation by APCs and induction of Ag-specific CD4+ and CD8+ T-cell responses in vitro and in vivo.