title: Local and systemic humoral immune response during acute and chronic Acanthamoeba keratitis in rabbits.
abstract: OBJECTIVE
  To study local and systemic antibody responses during the course of acute and chronic Acanthamoeba keratitis in a rabbit model. The role of secretory IgA (sIgA) in innate and adaptive immunity is investigated.
  
  
  METHODS
  Acanthamoeba keratitis was induced by intrastromal injection of live trophozoites in rabbits with and without prior oral immunization with aqueous Acanthamoeba antigen. The severity score of the ensuing keratitis was followed. Anti-Acanthamoeba antibodies in tears and sera were determined before infection and on a weekly basis postinfection for 6 weeks. The role of mucosal IgA as a link between the innate and adaptive immunity to Acanthamoeba was evaluated.
  
  
  RESULTS
  Acanthamoeba keratitis was significantly milder in animals infected after oral immunization than in naïve animals. Mucosal sIgA bound Acanthamoeba in a concentration-dependent, mannose-mediated manner. It significantly inhibited Acanthamoeba binding to rabbit corneal epithelium in vitro and in vivo. Anti-Acanthamoeba IgA significantly influenced amoebic lysis by neutrophils.
  
  
  CONCLUSIONS
  Mucosal IgA protects the external ocular surface by virtue of anti-adhesin properties displayed by the mannosylated residues on the heavy chains of IgA molecule (innate immunity) as well as specific antigen-binding sites (adaptive immunity). Immune IgA also augmented neutrophil-mediated amoebic lysis (adaptive immunity).
authors.affiliation: Parasitology Department, Research Institute of Ophthalmology, Giza, Egypt. nsaid@mail.mcg.edu
authors.forename: Neveen A
authors.initials: NA
authors.lastname: Said
authors.forename: Ahmed T
authors.initials: AT
authors.lastname: Shoeir
authors.forename: Noorjahan
authors.initials: N
authors.lastname: Panjwani
authors.forename: Marco
authors.initials: M
authors.lastname: Garate
authors.forename: Zhiyi
authors.initials: Z
authors.lastname: Cao
mesh_terms: D000048:Acanthamoeba / Q000276:immunology*; D015823:Acanthamoeba Keratitis / Q000276:immunology*; D000208:Acute Disease; D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood*; D000917:Antibody Formation; D000953:Antigens, Protozoan / Q000276:immunology; D015153:Blotting, Western; D002908:Chronic Disease; D003319:Corneal Stroma / Q000469:parasitology; D004195:Disease Models, Animal; D019084:Fluorescent Antibody Technique, Indirect; D007113:Immunity, Innate; D018928:Immunity, Mucosal; D007071:Immunoglobulin A, Secretory / Q000276:immunology*; D007074:Immunoglobulin G / Q000276:immunology*; D009504:Neutrophils / Q000276:immunology; D011817:Rabbits; D013666:Tears / Q000276:immunology*
chemical_list: D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D007071:Immunoglobulin A, Secretory; D007074:Immunoglobulin G