The present invention concerns a chimeric polypeptide comprising several polypeptide domains, which is capable of being secreted in association with membrane vesicles and in particular exosomes. The present invention also concerns a polypeptide constituted by one of said domains for the secretion of a peptide or polypeptide of interest in association with membrane vesicles and in particular exosomes. The invention also concerns the use of polypeptides of the invention and of polynucleotides coding for said polypeptides for the production of immunogenic compositions based on exosomes or based on DNA or for screening protein interactions. The present invention also concerns exploiting the properties of exosomes comprising a polypeptide of the invention and of immunogenic compositions of the invention for the prophylaxis and/or treatment of an infection by a pathogenic agent, a pathogenic organism, a tumour antigen or a cytoplasmic antigen, in particular to elicit or promote, in vivo, in a host, in particular in a human or non-human mammal or a bird, a humoral and/or cellular response against a virus, bacterium, parasite or tumour.

Provided herein, inter alia, are compositions for treating Human T-cell lymphotropic virus type 1 (HTLV-1) associated diseases. The compositions include a protein having a zinc finger domain capable of binding a sequence within an HTLV-1 long terminal repeat (LTR). Further provided are methods of treating HTLV-1 associated diseases in a subject in need thereof. The methods include administering to the subject the protein including the zinc finger domain, or a nucleic acid encoding the protein.