Homodimeric protein constructs

A vector comprising a nucleic acid molecule encoding a monomeric protein,

• wherein the monomeric protein forms a homodimeric protein of two identical amino acid chains,
• wherein each amino acid chain comprises:
• a) a targeting unit comprising an amino acid sequence having at least 98% sequence identity to the amino acid sequence set forth in positions 5-70 of SEQ ID NO:
• 1;
• b) and an antigenic unit,
• wherein the targeting unit and the antigenic unit are connected through a dimerization motif and
• wherein said homodimeric protein provides MHC class I cross-presentation to CD8+ T cells, and is capable of eliciting an immune response against said antigenic unit.