Investigation of liposomal self-adjuvanting peptide epitopes derived from conserved blood-stage Plasmodium antigens

PLoS One. 2022 Mar 11;17(3):e0264961. doi: 10.1371/journal.pone.0264961. eCollection 2022.

Abstract

Malaria is a vector born parasitic disease causing millions of deaths every year. Despite the high mortality rate, an effective vaccine against this mosquito-borne infectious disease is yet to be developed. Up to date, RTS,S/AS01 is the only vaccine available for malaria prevention; however, its efficacy is low. Among a variety of malaria antigens, merozoite surface protein-1(MSP-1) and ring-infected erythrocyte surface antigen (RESA) have been proposed as promising candidates for malaria vaccine development. We developed peptide-based Plasmodium falciparum vaccine candidates that incorporated three previously reported conserved epitopes from MSP-1 and RESA into highly effective liposomal polyleucine delivery system. Indeed, MSP-1 and RESA-derived epitopes conjugated to polyleucine and formulated into liposomes induced higher epitope specific antibody titres. However, immunized mice failed to demonstrate protection in a rodent malaria challenge study with Plasmodium yoelii. In addition, we found that the three reported P. falciparum epitopes did not to share conformational properties and high sequence similarity with P. yoelii MSP-1 and RESA proteins, despite the epitopes were reported to protect mice against P. yoelii challenge.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adjuvants, Immunologic
  • Animals
  • Antibodies, Protozoan
  • Antigens, Protozoan
  • Antigens, Surface
  • Epitopes
  • Liposomes
  • Malaria* / prevention & control
  • Merozoite Surface Protein 1
  • Mice
  • Peptides
  • Plasmodium falciparum
  • Plasmodium*
  • Protozoan Proteins
  • Vaccines, Subunit

Substances

  • Adjuvants, Immunologic
  • Antibodies, Protozoan
  • Antigens, Protozoan
  • Antigens, Surface
  • Epitopes
  • Liposomes
  • Merozoite Surface Protein 1
  • Peptides
  • Protozoan Proteins
  • Vaccines, Subunit

Grants and funding

The authors acknowledge funding from the Australian Research Council (Grant ID: DP21010280), the National Health and Medical Research Council (NHMRC) (Program Grant ID:1132975) and an Australian Government Research Training Program (RTP) Scholarship. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.