title: Immunogenicity of bioactive magnetic nanoparticles: natural and acquired antibodies.
abstract: Uniform magnetic nanoparticles (MNP) were prepared by nucleation followed by controlled growth of maghemite thin films onto porcine gelatin nuclei. The formed gelatin containing MNP (Gel-MNP) were then coated with dextran (Gel-MNP-Dex) followed by human serum albumin (Gel-MNP-Dex-HSA). Since these MNP are designated for clinical applications, studies concerning the immunogenicity of their antigenic components (porcine gelatin, dextran, and HSA) have been performed in BALB-C mice. These studies demonstrated that plasma of nonimmunized mice already contains basal levels of natural antibodies against all of these antigenic components. This work also demonstrated that the conjugated gelatin is a weak immunogen: Intraperitoneal injection of the various MNP (Gel-MNP, Gel-MNP-Dex dispersed in PBS emulsified with Incomplete Freund's Adjuvant (IFA) mineral oil and Gel-MNP-Dex-HSA dispersed in PBS) did not increase significantly the acquired anti-gelatin antibody titers. Exceptional behavior was observed following immunization with Gel-MNP-Dex-HSA dispersed in PBS emulsified with IFA, which exhibited an adjuvant effect and turned gelatin into a stronger immunogen. In contrast to gelatin, the conjugated HSA and dextran were found to be strong immunogens. The possibility that the various MNP will not induce an autoimmune response as a result of their clinical use is discussed in the contest of the protective role of the natural antibodies.
authors.affiliation: Department of Chemistry, Bar-Ilan University, Ramat-Gan 52900, Israel.
authors.forename: Ofra
authors.initials: O
authors.lastname: Ziv
authors.forename: Ramy R
authors.initials: RR
authors.lastname: Avtalion
authors.forename: Shlomo
authors.initials: S
authors.lastname: Margel
mesh_terms: D000818:Animals; D000906:Antibodies / Q000276:immunology*; D000941:Antigens / Q000276:immunology; D003432:Cross-Linking Reagents / Q000494:pharmacology; D003911:Dextrans / Q000378:metabolism; D005260:Female; D005782:Gels / Q000378:metabolism; D006801:Humans; D008280:Magnetics; D013058:Mass Spectrometry; D051379:Mice; D008807:Mice, Inbred BALB C; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles / Q000737:chemistry; D010316:Particle Size; D012709:Serum Albumin / Q000378:metabolism; D013552:Swine; D013696:Temperature; D013818:Thermogravimetry; D014961:X-Ray Diffraction
chemical_list: D000906:Antibodies; D000941:Antigens; D003432:Cross-Linking Reagents; D003911:Dextrans; D005782:Gels; D012709:Serum Albumin