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Advances in the Assessment of Plasmodium falciparum Pfs47 as a Transmission Blocking Target

Wednesday, September 13, 2017 — Poster Session II

3:30 p.m. – 5:00 p.m.
FAES Terrace
NIAID
MICROBIO-6

Authors

  • GE Canepa
  • A Molina-Cruz
  • L Douti
  • C Barillas-Mury

Abstract

Malaria transmission-blocking vaccines rely on functional antibodies that interact with proteins present on the surface of sexual/sporogonic stages of Plasmodium or in the mosquito midgut and disrupt vector-parasite interactions critical for malaria transmission. We recently identified the surface female gametocyte protein Pfs47 as a key determinant of parasite immune evasion in the mosquito vector. We investigated whether antibodies to Pfs47 can inhibit parasite transmission to mosquitoes. After attempting several different strategies, recombinant proteins were expressed in E. coli cells, followed by mouse immunization and monoclonal antibody (mAb) production. More than ten mAbs generated against the full length Pfs47 showed modest and variable transmission-reducing activity. Interestingly enough, none of these mAbs reacted against a particular region of the full-length Pfs47 protein. After several strategies, a modified version of this Pfs47 specific region was expressed in E. coli for polyclonal and monoclonal antibody production. Purified IgG from sera of immunized mice used in a standard membrane feeding assay showed a robust and reproducible transmission-reducing activity when compared to naïve purified mouse IgG. Two independent spleen fusions were carried out using the immunized mice for monoclonal antibody production. Ten monoclonal antibodies were obtained which showed different patterns of recognition against Pfs47 by ELISA and Western Blot, which will be discussed. Preliminary results obtained from standard membrane feeding assays using purified IgG from cloned independent hybridomas will also be discussed.

Category: Microbiology and Infectious Diseases