Polymerisation of a T cell epitope with an immunostimulatory C3d peptide sequence enhances antigen specific T cell responses

Abstract

The complement protein C3d and C3d derived peptides that bind CD21 are known to enhance immunity to co-immunised antigens. In this study we have synthesised the minimal CD21 binding sequence of C3d (1227LYNVEA 1232) as mono, di and tri tandem repeats and derivatised the N-terminus with an acryloyl moiety. These acryloyl-(C3d) n peptides were co-polymerised with a acryloyl-T cell epitope (PAS1K) from the Porphyromonas gingivalis antigen the RgpA-Kgp proteinase-adhesin complex. The ability of C3d containing polymers to enhance T cell immunity in vitro and in vivo was evaluated. When used to stimulate in vitro PAS1K-primed or RgpA-Kgp complex-primed T cells the C3d containing PAS1K polymers ind..