title: Immunological evidence and regulatory potential for cell-penetrating antibodies in intravenous immunoglobulin.
abstract: Anti-DNA cell-penetrating autoantibodies have been extensively studied in autoimmune but not in normal sera. We investigated herein the presence and properties of cell-penetrating antibodies (CPAbs) in intravenous immunoglobulin (IVIg), a blood product of pooled normal human IgG. IVIg cell penetration was observed into various cell lines, as well as cells from several organs of mice injected intravenously with IVIg therapeutic dose. In all cell types examined in vitro and in vivo, intracellular IgG localized in the cytoplasm, in contrast to the nuclear accumulation of disease-related CPAbs. IVIg was found to rapidly enter cells via an energy-independent mode. The CPAb-fraction was isolated and found to be polyreactive to nuclear and cytoplasmic components; although it corresponded to ~2% of IVIg, it accounted for its inhibitory effect on splenocyte activation. Investigation of IVIg cell penetration capacity provides insight into its mechanisms of action and may account for some of its beneficial effects in numerous diseases.
authors.affiliation: Department of Immunology, Immunology Laboratory, Hellenic Pasteur Institute , Athens, Greece.
authors.forename: Aggeliki D
authors.initials: AD
authors.lastname: Sali
authors.affiliation: Department of Microbiology, Molecular Virology Laboratory, Hellenic Pasteur Institute , Athens, Greece.
authors.forename: Ioannis
authors.initials: I
authors.lastname: Karakasiliotis
authors.affiliation: Department of Immunology, Molecular Genetics Laboratory, Hellenic Pasteur Institute , Athens, Greece.
authors.forename: Maria
authors.initials: M
authors.lastname: Evangelidou
authors.affiliation: Department of Immunology, Immunology Laboratory, Hellenic Pasteur Institute , Athens, Greece.
authors.forename: Stratis
authors.initials: S
authors.lastname: Avrameas
authors.affiliation: Department of Immunology, Immunology Laboratory, Hellenic Pasteur Institute , Athens, Greece.
authors.forename: Peggy
authors.initials: P
authors.lastname: Lymberi