Human T-cell recognition of synthetic peptides representing conserved and variant sequences from the merozoite surface protein 2 of Plasmodium falciparum

Immunol Lett. 1997 Jun;58(1):1-8. doi: 10.1016/s0165-2478(96)02685-5.

Abstract

Merozoite surface protein 2 (MSP2) is a malaria vaccine candidate currently undergoing clinical trials. We analyzed the peripheral blood mononuclear cell (PBMC) response to synthetic peptides corresponding to conserved and variant regions of the FCQ-27 allelic form of MSP2 in Ghanaian individuals from an area of hyperendemic malaria transmission and in Danes without exposure to malaria. PBMC from 20-39% of Ghanaians responded to each of the peptides by proliferation and 29-36% had PBMC which produced interferon-gamma (IFN-gamma) in response to peptide stimulation. In Danes, there was no proliferation to two of the peptides and only PBMC from 5% of the individuals proliferated to the other three peptides. IFN-gamma production was not detected to any peptide. In both Danes and Ghanaians in only a few instances was IL-4 detected in the PBMC cultures. Overall PBMC from 79% of the Ghanaians responded by proliferation and/or cytokine secretion to at least one of three peptides tested, whereas responses were only observed in 14% of Danes (P = 0.002). These data suggest that the Ghanaians had expanded peripheral blood T-cell populations recognizing the peptides as a result of natural infection. The findings are encouraging for the development of a vaccine based on these T-epitope containing regions of MSP2, as the peptides were broadly recognized suggesting that they can bind to diverse HLA alleles and also because they include conserved MSP2 sequences. Immunisation with a vaccine construct incorporating the sequences present in these peptides could thus be expected to be immunogenic in a high percentage of individuals and lead to the establishment of memory T-cells, which can be boosted through natural infection.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Amino Acid Sequence
  • Animals
  • Antigens, Protozoan*
  • Conserved Sequence
  • Denmark
  • Genetic Variation
  • Ghana
  • Humans
  • Interferon-gamma / analysis
  • Interleukin-4 / analysis
  • Lymphocyte Activation
  • Malaria Vaccines / immunology*
  • Malaria, Falciparum / epidemiology
  • Malaria, Falciparum / immunology
  • Molecular Sequence Data
  • Peptide Fragments / immunology
  • Plasmodium falciparum / immunology*
  • Protozoan Proteins / immunology*
  • T-Lymphocytes / immunology*

Substances

  • Antigens, Protozoan
  • Malaria Vaccines
  • Peptide Fragments
  • Protozoan Proteins
  • merozoite surface protein 2, Plasmodium
  • Interleukin-4
  • Interferon-gamma