An artificial virus-like triblock protein shows low in vivo humoral immune response and high stability

The use of viral vectors for in vivo gene therapy can be severely limited by their immunogenicity. Non-viral vectors may represent an alternative, however, reports analyzing their immunogenicity are still lacking. Here, we studied the humoral immune response in a murine model triggered by artificial virus-like particles (AVLPs) carrying plasmid or antisense DNA. The AVLPs were assembled using a family of modular proteins based on bioinspired collagen-like and silk-like sequences that produce virus-like particles. We compared our AVLPs against an Adeno Associated Virus 1 (AAV), a widely used viral vector for in vivo gene delivery that has been approved by the FDA and EMA for gene therapy. We found that a 1000-fold higher mass of AVLPs than AAV are necessary to obtain similar specific antibody titters. Furthermore, we studied the stability of AVLPs against relevant biological reagents such as heparin and fetal bovine serum to ensure nucleic acid protection in biological media. Our study demonstrates that the AVLPs are stable in physiological conditions and can overcome safety limitations such as immunogenicity. The scarce humoral immunogenicity and high stability found with AVLPs suggest that they have potential to be used as stealth non-viral gene delivery systems for in vivo studies or gene therapy.