title: Physical Characterization and Innate Immunogenicity of Aggregated Intravenous Immunoglobulin (IGIV) in an In Vitro Cell-Based Model.
abstract: To investigate in vitro the innate immune response to accelerated stress-induced aggregates of intravenous immunoglobulin (IGIV) using a well-defined human cell-line model, and to correlate the innate response to physical properties of the aggregates.
  
  
  
  IGIV aggregates were prepared by applying various accelerated stress methods, and particle size, count and structure were characterized. Immune cell activation as tracked by inflammatory cytokines released in response to aggregates was evaluated in vitro using peripheral blood mononuclear cells (PBMC), primary monocytes and immortalized human monocyte-like cell lines.
  
  
  
  IGIV aggregates produced by mechanical stress induced higher cytokine release by PBMC and primary monocytes than aggregates formed by other stresses. Results with the monocytic cell line THP-1 paralleled trends in PBMC and primary monocytes. Effects were dose-dependent, enhanced by complement opsonization, and partially inhibited by blocking toll-like receptors (TLR2 and TLR4) and to a lesser extent by blocking Fc gamma receptors (FcγRs).
  
  
  
  Stress-induced IGIV aggregates stimulate a dose-dependent cytokine response in human monocytes and THP-1 cells, mediated in part by TLRs, FcγRs and complement opsonization. THP-1 cells resemble primary monocytes in many respects with regard to tracking the innate response to IgG aggregates. Accordingly, the measurement of inflammatory cytokines released by THP-1 cells provides a readily accessible assay system to screen for the potential innate immunogenicity of IgG aggregates. The results also highlight the role of aggregate structure in interacting with the different receptors mediating innate immunity.
authors.affiliation: Department of Industrial and Physical Pharmacy, College of Pharmacy, Purdue University, 575 Stadium Mall Drive, 47906, West Lafayette, Indiana, USA.
authors.forename: E M
authors.initials: EM
authors.lastname: Moussa
authors.affiliation: Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, Maryland, USA.|Brand Institute, Rockville, Maryland, USA.
authors.forename: J
authors.initials: J
authors.lastname: Kotarek
authors.affiliation: Department of Microbiology and Immunology, School of Medicine, Indiana University, Indianapolis, Indiana, USA.
authors.forename: J S
authors.initials: JS
authors.lastname: Blum
authors.affiliation: Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, Maryland, USA.
authors.forename: E
authors.initials: E
authors.lastname: Marszal
authors.affiliation: Department of Industrial and Physical Pharmacy, College of Pharmacy, Purdue University, 575 Stadium Mall Drive, 47906, West Lafayette, Indiana, USA. topp@purdue.edu.
authors.forename: E M
authors.initials: EM
authors.lastname: Topp
mesh_terms: D000917:Antibody Formation / Q000276:immunology*; D002460:Cell Line; D016207:Cytokines / Q000276:immunology; D006801:Humans; D007113:Immunity, Innate / Q000276:immunology*; D016756:Immunoglobulins, Intravenous / Q000276:immunology*; D007963:Leukocytes, Mononuclear / Q000276:immunology; D009000:Monocytes / Q000276:immunology; D010316:Particle Size; D017452:Receptors, IgG / Q000276:immunology; D051193:Toll-Like Receptors / Q000276:immunology
chemical_list: D016207:Cytokines; D016756:Immunoglobulins, Intravenous; D017452:Receptors, IgG; D051193:Toll-Like Receptors
keywords: immunogenicity; immunoglobulin; monocytes; protein aggregates