title: Humoral immune response against epidermal growth factor encapsulated in dehydration rehydration vesicles of different phospholipid composition.
abstract: We investigated the influence of dehydration-rehydration vesicles (DRV) phospholipid composition and the addition of other components on human recombinant epidermal growth factor (hrEGF) encapsulation efficiency and its release from liposomes. Encapsulation of EGF into DRV composed of phosphatidylcholine with different unsaturation levels was around 20-35%. The best result was obtained with dipalmitoyl phosphatidylcholine: cholesterol (DPPC:Ch) liposomes (35%) corresponding to the lowest hrEGF release during one month of storage. Even with this phospholipid composition, modification of the DRV procedure by including an extrusion step did not improve hrEGF encapsulation efficiency, rendering less stable particles. The inclusion of recombinant P64k from Neisseria meningitidis (rP64k), as such or conjugated to hrEGF, decreased the encapsulation efficiency of the latter protein into DRV or freeze and thaw multilamellar vesicles (FATMLV). The hrEGF release from liposomes could be related to the interaction between this polypeptide and the bilayer, as evidenced by increased carboxyfluorescein release from hrEGF-DRV; less susceptibility to fluorescence quenching by acrylamide in the presence of liposomes; and a measurable decrease of phospholipid phase transition Delta enthalpy (DeltaH). DRV comprising saturated phospholipids (DPPC:Ch or distearoyl phosphatidylcholine [DSPC]:Ch) and containing the conjugate EGF-P64k induced a more efficient immune response against hrEGF than unsaturated phospholipid and alum in terms of total IgG, IgG(2a), and IgG(2b) subclasses and the ability of antibody to inhibit the interaction of the EGF receptor with hrEGF.
authors.affiliation: Center for Protein Study and Department of Biochemistry, Faculty of Biology, University of Havana, Ciudad de la Habana, Cuba. mlanio@infomed.sld.cu
authors.forename: M E
authors.initials: ME
authors.lastname: Lanio
authors.forename: M C
authors.initials: MC
authors.lastname: Luzardo
authors.forename: C
authors.initials: C
authors.lastname: Alvarez
authors.forename: Y
authors.initials: Y
authors.lastname: Martínez
authors.forename: L
authors.initials: L
authors.lastname: Calderón
authors.forename: M E
authors.initials: ME
authors.lastname: Alonso
authors.forename: B
authors.initials: B
authors.lastname: Zadi
authors.forename: G
authors.initials: G
authors.lastname: Gregoriadis
authors.forename: D Q M
authors.initials: DQ
authors.lastname: Craig
authors.forename: A
authors.initials: A
authors.lastname: Disalvo
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000378:metabolism; D002152:Calorimetry, Differential Scanning / Q000379:methods; D003890:Desiccation; D004815:Epidermal Growth Factor / Q000378:metabolism*; D005452:Fluoresceins / Q000378:metabolism; D006801:Humans; D007107:Immune System; D007074:Immunoglobulin G / Q000737:chemistry; D008051:Lipid Bilayers / Q000737:chemistry; D008081:Liposomes / Q000737:chemistry / Q000378:metabolism; D051379:Mice; D009345:Neisseria meningitidis / Q000378:metabolism; D010743:Phospholipids / Q000737:chemistry*; D013816:Thermodynamics
chemical_list: D001426:Bacterial Proteins; D005452:Fluoresceins; D007074:Immunoglobulin G; D008051:Lipid Bilayers; D008081:Liposomes; D010743:Phospholipids; C024098:6-carboxyfluorescein; D004815:Epidermal Growth Factor