A simple, ex vivo phagocytosis assay of Plasmodium vivax merozoites by flow cytometry

Mem Inst Oswaldo Cruz. 2019 Oct 7:114:e190158. doi: 10.1590/0074-02760190158. eCollection 2019.

Abstract

As phagocytosis is the first line of defense against malaria, we developed a phagocytosis assay with Plasmodium vivax (P. vivax) merozoites that can be applied to evaluate vaccine candidates. Briefly, after leukocyte removal with loosely packed cellulose powder in a syringe, P. vivax trophozoites matured to the merozoite-rich schizont stages in the presence of the E64 protease inhibitor. The Percoll gradient-enriched schizonts were chemically disrupted to release merozoites that were submitted to merozoite opsonin-dependent phagocytosis in two phagocytic lines with human and mouse antibodies against the N- and C-terminus of P. vivax Merozoite Surface Protein-1 (Nterm-PvMSP1 and MSP119). The resulting assay is simple and efficient for use as a routine phagocytic assay for the evaluation of merozoite stage vaccine candidates.

MeSH terms

  • Animals
  • Antibodies, Protozoan / immunology*
  • Female
  • Flow Cytometry
  • Merozoites / cytology
  • Merozoites / immunology*
  • Mice
  • Mice, Inbred BALB C
  • Phagocytosis / physiology*
  • Plasmodium vivax / immunology*
  • Plasmodium vivax / physiology
  • Protozoan Proteins / immunology*

Substances

  • Antibodies, Protozoan
  • Protozoan Proteins