title: Rational design of protamine nanocapsules as antigen delivery carriers.
abstract: Current challenges in global immunization indicate the demand for new delivery strategies, which could be applied to the development of new vaccines against emerging diseases, as well as to improve safety and efficacy of currently existing vaccine formulations. Here, we report a novel antigen nanocarrier consisting of an oily core and a protamine shell, further stabilized with pegylated surfactants. These nanocarriers, named protamine nanocapsules, were rationally designed to promote the intracellular delivery of antigens to immunocompetent cells and to trigger an efficient and long-lasting immune response. Protamine nanocapsules have nanometric size, positive zeta potential and high association capacity for H1N1 influenza hemagglutinin, a protein that was used here as a model antigen. The new formulation shows an attractive stability profile both, as an aqueous suspension or a freeze-dried powder formulation. In vitro studies showed that protamine nanocapsules were efficiently internalized by macrophages without eliciting significant toxicity. In vivo studies indicate that antigen-loaded nanocapsules trigger immune responses comparable to those achieved with alum, even when using significantly lower antigen doses, thus indicating their adjuvant properties. These promising in vivo data, alongside with their versatility for the loading of different antigens and oily immunomodulators and their excellent stability profile, make these nanocapsules a promising platform for the delivery of antigens.
  
  
  
  Protamine sulphate (PubChem SID: 7849283), Sodium Cholate (PubChem CID: 23668194), Miglyol (PubChem CID: 53471835), α tocopherol (PubChem CID: 14985), Tween® 20(PubChem CID: 443314), Tween® 80(PubChem CID: 5281955), TPGS (PubChem CID: 71406).
authors.affiliation: Center for Research in Molecular Medicine and Chronic Diseases (CIMUS), Health Research Institute of Santiago de Compostela (IDIS), Dept. of Pharmacy and Pharmaceutical Technology, School of Pharmacy, Univ. of Santiago de Compostela, 15872 Santiago de Compostela, Spain; Departamento de Farmacia, Facultad de Química, Pontificia Universidad Católica de Chile, 7820436 Santiago, Chile. Electronic address: jvgonzal@uc.cl.
authors.forename: José Vicente
authors.initials: JV
authors.lastname: González-Aramundiz
authors.affiliation: Center for Research in Molecular Medicine and Chronic Diseases (CIMUS), Health Research Institute of Santiago de Compostela (IDIS), Dept. of Pharmacy and Pharmaceutical Technology, School of Pharmacy, Univ. of Santiago de Compostela, 15872 Santiago de Compostela, Spain. Electronic address: elena.presas89@gmail.com.
authors.forename: Elena
authors.initials: E
authors.lastname: Presas
authors.affiliation: Departamento de Biotecnología, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), 28040 Madrid, Spain. Electronic address: dalinm81@gmail.com.
authors.forename: Inmaculada
authors.initials: I
authors.lastname: Dalmau-Mena
authors.affiliation: Alternative Gene Expression S.L. (ALGENEX), Centro empresarial, Parque Científico y Tecnológico de la Universidad Politécnica de Madrid, Campus de Montegancedo, 28223 Madrid, Spain. Electronic address: smartinez@algenex.com.
authors.forename: Susana
authors.initials: S
authors.lastname: Martínez-Pulgarín
authors.affiliation: Departamento de Biotecnología, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), 28040 Madrid, Spain. Electronic address: calonso@inia.es.
authors.forename: Covadonga
authors.initials: C
authors.lastname: Alonso
authors.affiliation: Departamento de Biotecnología, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), 28040 Madrid, Spain. Electronic address: escriban@inia.es.
authors.forename: José M
authors.initials: JM
authors.lastname: Escribano
authors.affiliation: Center for Research in Molecular Medicine and Chronic Diseases (CIMUS), Health Research Institute of Santiago de Compostela (IDIS), Dept. of Pharmacy and Pharmaceutical Technology, School of Pharmacy, Univ. of Santiago de Compostela, 15872 Santiago de Compostela, Spain. Electronic address: mariaj.alonso@usc.es.
authors.forename: María J
authors.initials: MJ
authors.lastname: Alonso
authors.affiliation: Center for Research in Molecular Medicine and Chronic Diseases (CIMUS), Health Research Institute of Santiago de Compostela (IDIS), Dept. of Pharmacy and Pharmaceutical Technology, School of Pharmacy, Univ. of Santiago de Compostela, 15872 Santiago de Compostela, Spain. Electronic address: noemi.csaba@usc.es.
authors.forename: Noemi Stefánia
authors.initials: NS
authors.lastname: Csaba
mesh_terms: D000818:Animals; D000956:Antigens, Viral / Q000008:administration & dosage* / Q000737:chemistry; D002470:Cell Survival / Q000187:drug effects; D004337:Drug Carriers / Q000008:administration & dosage* / Q000737:chemistry; D005260:Female; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000008:administration & dosage* / Q000737:chemistry; D007114:Immunization; D007074:Immunoglobulin G / Q000097:blood; D051379:Mice; D008807:Mice, Inbred BALB C; D053769:Nanocapsules / Q000008:administration & dosage* / Q000737:chemistry; D011479:Protamines / Q000008:administration & dosage* / Q000737:chemistry; D000067996:RAW 264.7 Cells
chemical_list: D000956:Antigens, Viral; D004337:Drug Carriers; C543345:H1N1 virus hemagglutinin; D019267:Hemagglutinin Glycoproteins, Influenza Virus; D007074:Immunoglobulin G; D053769:Nanocapsules; D011479:Protamines
keywords: Adjuvant; Antigen delivery; Influenza vaccine; Nanocapsules; Protamine; Vaccine