Abstract: The present invention provides a chimeric protein that has a modular structure and comprises a receptor binding domain (RBD) from the spike protein (S) of coronaviruses, a segment able to bind the core antigen from the Hepatitis B Virus (HBcAg), a segment including six consecutive histidine residues (HHHHHH), and two spacer segments. In this chimeric protein the aforementioned segments are arranged in a specific order, and the protein is able to form hybrid nanoparticles with HBcAg. The chimeric protein is part of vaccine compositions used for the prevention of coronavirus infections. Therefore, the invention discloses a method for the prevention of coronavirus infections, whereby a vaccine composition comprising said chimeric protein is administered.

Abstract: Chimeric antigen comprising multimeric aggregates of the extracellular domain of the programmed death ligand 1 (PD-L1) with a reduced binding capacity to the PD-1 and CD80 receptors as compared to the native PD-L1 molecule. The invention further discloses pharmaceutical compositions including said chimeric antigen and at least a pharmaceutically acceptable vaccine adjuvant. The chimeric antigen is used for the manufacturing of a drug to treat cancer or its metastases. The invention also discloses a method of treating cancer or its metastases in a subject in need thereof, characterized by the administration of a therapeutically effective amount of the pharmaceutical composition comprising the chimeric antigen described herein.

Abstract: Polypeptides comprising functional mutants of an isoform of the human vascular endothelial growth factor A (VEGF-A) folded in a non-natural re-arrangement, where the second and fourth cysteine of the mutant's polypeptide chain is only forming intramolecular bridges, while the seventh and eight are only part of intermolecular bonds. The invention further comprises antigenic preparations containing at least one of these polypeptides, and the pharmaceutical compositions comprising such antigenic preparations and vaccine adjuvants. The antigenic preparations according to the invention are used in the manufacturing of a drug, for the treatment of diseases related to the increment of angiogenesis, inflammation, and immunosuppression, as well as for the restoration of the immune system.