title: Immunization with L. sigmodontis microfilariae reduces peripheral microfilaraemia after challenge infection by inhibition of filarial embryogenesis.
abstract: BACKGROUND
  Lymphatic filariasis and onchocerciasis are two chronic diseases mediated by parasitic filarial worms causing long term disability and massive socioeconomic problems. Filariae are transmitted by blood-feeding mosquitoes that take up the first stage larvae from an infected host and deliver it after maturation into infective stage to a new host. After closure of vector control programs, disease control relies mainly on mass drug administration with drugs that are primarily effective against first stage larvae and require many years of annual/biannual administration. Therefore, there is an urgent need for alternative treatment ways, i.e. other effective drugs or vaccines.
  
  
  RESULTS
  Using the Litomosoides sigmodontis murine model of filariasis we demonstrate that immunization with microfilariae together with the adjuvant alum prevents mice from developing high microfilaraemia after challenge infection. Immunization achieved 70% to 100% protection in the peripheral blood and in the pleural space and furthermore strongly reduced the microfilarial load in mice that remained microfilaraemic. Protection was associated with the impairment of intrauterine filarial embryogenesis and with local and systemic microfilarial-specific host IgG, as well as IFN-γ secretion by host cells from the site of infection. Furthermore immunization significantly reduced adult worm burden.
  
  
  CONCLUSIONS
  Our results present a tool to understand the immunological basis of vaccine induced protection in order to develop a microfilariae-based vaccine that reduces adult worm burden and prevents microfilaraemia, a powerful weapon to stop transmission of filariasis.
authors.affiliation: Institute of Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Ziewer
authors.forename: Marc P
authors.initials: MP
authors.lastname: Hübner
authors.forename: Bettina
authors.initials: B
authors.lastname: Dubben
authors.forename: Wolfgang H
authors.initials: WH
authors.lastname: Hoffmann
authors.forename: Odile
authors.initials: O
authors.lastname: Bain
authors.forename: Coralie
authors.initials: C
authors.lastname: Martin
authors.forename: Achim
authors.initials: A
authors.lastname: Hoerauf
authors.forename: Sabine
authors.initials: S
authors.lastname: Specht
mesh_terms: D000276:Adjuvants, Immunologic / Q000008:administration & dosage; D000534:Alum Compounds / Q000008:administration & dosage; D000818:Animals; D004195:Disease Models, Animal; D005260:Female; D005368:Filariasis / Q000276:immunology / Q000517:prevention & control*; D005370:Filarioidea / Q000254:growth & development / Q000276:immunology* / Q000302:isolation & purification; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D059208:Parasite Load; D018512:Parasitemia / Q000517:prevention & control*; D014611:Vaccination / Q000379:methods; D014612:Vaccines / Q000008:administration & dosage* / Q000276:immunology*
chemical_list: D000276:Adjuvants, Immunologic; D000534:Alum Compounds; D014612:Vaccines; C041524:aluminum sulfate