Kunitz-type protease inhibitor as a vaccine candidate against schistosomiasis mansoni

Int J Infect Dis. 2018 Jan:66:26-32. doi: 10.1016/j.ijid.2017.10.024. Epub 2017 Nov 8.

Abstract

Objective: The aim of this study was to develop a vaccine against schistosomiasis, which is a major challenge due to the complex lifecycle of the causative schistosome parasite.

Methods: SmKI-1 is a 16-kDa Kunitz-type protease inhibitor present in the excretory-secretory products and tegument of adult worms and eggs of Schistosoma mansoni. Two independent vaccine trials were performed in mice to determine the efficacy of rSmKI-1 in developing protective immunity.

Results: The results obtained showed reductions of 23-33% in adult worms, 28-31% in intestinal eggs, 33-39% in faecal eggs, and 20-43% in liver eggs. Furthermore, rSmKI-1 significantly increased the production of interferon gamma, interleukin (IL)-10, and IL-6 in vaccinated mice, maintaining a Th1/Th2-type balanced protective response.

Conclusions: rSmKI-1 generated partial protection against schistosomiasis mansoni in the murine model of infection and could be developed as part of a combination vaccine with other vaccine candidates to provide an even more solid level of protection.

Keywords: ES products; Kunitz protein; Schistosomiasis mansoni; SmKI-1.

MeSH terms

  • Animals
  • Antigens, Helminth* / immunology
  • Egg Hypersensitivity
  • Female
  • Interferon-gamma
  • Interleukin-10
  • Interleukin-6
  • Mice
  • Mice, Inbred C57BL
  • Mice, Inbred CBA
  • Protease Inhibitors* / immunology
  • Schistosoma mansoni
  • Schistosomiasis mansoni / immunology
  • Schistosomiasis mansoni / prevention & control*
  • Vaccines* / immunology

Substances

  • Antigens, Helminth
  • IL10 protein, human
  • Interleukin-6
  • Protease Inhibitors
  • Vaccines
  • Interleukin-10
  • Interferon-gamma