title: Immunization with Recombinantly Expressed LRP4 Induces Experimental Autoimmune Myasthenia Gravis in C57BL/6 Mice.
abstract: BACKGROUND
  Myasthenia gravis (MG) is an autoimmune disease of the neuromuscular junction (NMJ), characterized with muscle weakness. While MG develops due to acetylcholine receptor (AChR) antibodies in most patients, antibodies to muscle-specific receptor tyrosine kinase (MuSK) or low-density lipoprotein receptor-related protein 4 (LRP4) may also be identified. Experimental autoimmune myasthenia gravis (EAMG) has been previously induced by both LRP4 immunization and passive transfer of LRP4 antibodies.
  
  
  OBJECTIVE
  Our aim was to confirm previous results and to test the pathogenic effects of LRP4 immunization in a commonly used mouse strain C57BL/6 (B6) using a recombinantly expressed human LRP4 protein.
  
  
  METHODS
  B6 mice were immunized with human LRP4 in CFA, Torpedo Californica AChR in CFA or only CFA. Clinical and pathogenic aspects of EAMG were compared among groups.
  
  
  RESULTS
  LRP4- and AChR-immunized mice showed comparable EAMG clinical severity. LRP4-immunized mice displayed serum antibodies to LRP4 and NMJ IgG and complement factor C3 deposits. IgG2 was the dominant anti-LRP4 isotype. Cultured lymph node cells of LRP4- and AChR-immunized mice gave identical pro-inflammatory cytokine (IL-6, IFN-γ and IL-17) responses to LRP4 and AChR stimulation, respectively.
  
  
  CONCLUSIONS
  Our results confirm the EAMG-inducing action of LRP4 immunization and identify B6 as a LRP4-EAMG-susceptible mouse strain. Demonstration of complement fixing anti-LRP4 antibodies in sera and complement/IgG deposits at the NMJ of LRP4-immunized mice indicates complement activation as a putative pathogenic mechanism. We have thus developed a practical LRP4-induced EAMG model using a non-conformational protein and a widely available mouse strain for future investigation of LRP4-related MG.
authors.affiliation: a Department of Neuroscience , Aziz Sancar Institute for Experimental Medical Research, Istanbul Faculty of Medicine, Istanbul University , Istanbul , Turkey.
authors.forename: Canan
authors.initials: C
authors.lastname: Ulusoy
authors.affiliation: b Department of Genetics, Aziz Sancar Institute for Experimental Medical Research, Istanbul Faculty of Medicine , Istanbul University , Istanbul , Turkey.
authors.forename: Filiz
authors.initials: F
authors.lastname: Çavuş
authors.affiliation: a Department of Neuroscience , Aziz Sancar Institute for Experimental Medical Research, Istanbul Faculty of Medicine, Istanbul University , Istanbul , Turkey.
authors.forename: Vuslat
authors.initials: V
authors.lastname: Yılmaz
authors.affiliation: a Department of Neuroscience , Aziz Sancar Institute for Experimental Medical Research, Istanbul Faculty of Medicine, Istanbul University , Istanbul , Turkey.
authors.forename: Erdem
authors.initials: E
authors.lastname: Tüzün
mesh_terms: D000818:Animals; D003167:Complement Activation / Q000187:drug effects*; D003176:Complement C3 / Q000378:metabolism; D005620:Freund's Adjuvant / Q000008:administration & dosage; D006801:Humans; D007114:Immunization / Q000379:methods*; D007074:Immunoglobulin G / Q000096:biosynthesis*; D007132:Immunoglobulin Isotypes / Q000096:biosynthesis; D007371:Interferon-gamma / Q000096:biosynthesis / Q000276:immunology; D020381:Interleukin-17 / Q000096:biosynthesis / Q000276:immunology; D015850:Interleukin-6 / Q000096:biosynthesis / Q000276:immunology; D026502:LDL-Receptor Related Proteins / Q000008:administration & dosage* / Q000276:immunology; D008198:Lymph Nodes / Q000187:drug effects / Q000276:immunology / Q000473:pathology; D008214:Lymphocytes / Q000187:drug effects / Q000276:immunology / Q000473:pathology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D020720:Myasthenia Gravis, Autoimmune, Experimental / Q000139:chemically induced / Q000276:immunology* / Q000473:pathology; D061251:Primary Cell Culture; D011950:Receptors, Cholinergic / Q000008:administration & dosage* / Q000276:immunology; D011994:Recombinant Proteins / Q000008:administration & dosage / Q000276:immunology; D012720:Severity of Illness Index; D014101:Torpedo / Q000378:metabolism
chemical_list: D003176:Complement C3; D007074:Immunoglobulin G; D007132:Immunoglobulin Isotypes; D020381:Interleukin-17; D015850:Interleukin-6; D026502:LDL-Receptor Related Proteins; C551781:LRP4 protein, human; D011950:Receptors, Cholinergic; D011994:Recombinant Proteins; C577686:interleukin-6, mouse; D007371:Interferon-gamma; D005620:Freund's Adjuvant
keywords: Antibody; LRP4; autoimmunity; immunization; myasthenia gravis