Preclinical prophylactic efficacy testing of Sm-p80-based vaccine in a nonhuman primate model of Schistosoma mansoni infection and immunoglobulin G and E responses to Sm-p80 in human serum samples from an area where schistosomiasis is endemic

J Infect Dis. 2011 Nov;204(9):1437-49. doi: 10.1093/infdis/jir545. Epub 2011 Sep 15.

Abstract

The prophylactic efficacy of a schistosome antigen (Sm-p80) was tested in a nonhuman primate model, the baboon. Using a total of 28 baboons, different vaccination strategies were used including recombinant Sm-p80 protein formulated in Toll-like receptor 7 and Toll-like receptor 9 agonists, and DNA priming followed by boosting with protein plus adjuvants. Recombinant protein approaches provided levels of prophylactic efficacy of 52%-58%, whereas prime-boost approaches conferred 38%-47% protection in baboons. An appropriately balanced pro-inflammatory (T-helper 17 [Th17] and Th1) and anti-inflammatory (Th2) type of response was generated; the Th1 and Th17 types of immune responses appear to be indicative of increased prophylactic efficacy. Production and expression of several cytokines (interleukin 2 [IL-2], interferon γ, IL-12α, IL-1β, IL-6, and IL-22) were up-regulated in vaccinated animals. Human correlate studies revealed Sm-p80 reactivity with immunoglobulin G in human serum samples from schistosome-infected individuals. In addition, a complete lack of prevailing Sm-p80-specific immunoglobulin E in a high-risk or infected population was observed, thus minimizing the risk of hypersensitivity reaction following vaccination with Sm-p80 in humans. This study provided the proof of concept to move Sm-p80 forward into further preclinical development leading to human clinical trials.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibodies, Helminth / blood*
  • Antigens, Helminth / administration & dosage
  • Antigens, Helminth / immunology*
  • Cytokines / metabolism
  • Disease Models, Animal
  • Endemic Diseases*
  • Female
  • Humans
  • Immunoglobulin E / blood
  • Immunoglobulin G / blood
  • Male
  • Papio
  • Primate Diseases / immunology
  • Primate Diseases / prevention & control
  • Schistosoma mansoni / immunology*
  • Schistosomiasis mansoni / immunology*
  • Schistosomiasis mansoni / prevention & control*
  • Serum / immunology
  • Vaccination / methods
  • Vaccines, DNA / administration & dosage
  • Vaccines, DNA / immunology*
  • Vaccines, Subunit / administration & dosage
  • Vaccines, Subunit / immunology

Substances

  • Antibodies, Helminth
  • Antigens, Helminth
  • Cytokines
  • Immunoglobulin G
  • Vaccines, DNA
  • Vaccines, Subunit
  • Immunoglobulin E