Publications & Reports

Unique T cell effector functions elicited by Plasmodium falciparum epitopes in malaria-exposed Africans tested by three T cell assays.

Flanagan KL, Lee EA, Gravenor MB, Reece WH, Urban BC, Doherty T, Bojang KA, Pinder M, Hill AV, Plebanski M
Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Headington, Oxford, United Kingdom. katflan@hotmail.com

Abstract

Natural immunity to malaria is characterized by low level CD4 T cell reactivity detected by either lymphoproliferation or IFN-gamma secretion. Here we show a doubling in the detection rate of responders to the carboxyl terminus of circumsporozoite protein (CS) of Plasmodium falciparum by employing three T cell assays simultaneously: rapid IFN-gamma secretion (ex vivo ELISPOT), IFN-gamma secretion after reactivation of memory T cells and expansion in vitro (cultured ELISPOT), and lymphoproliferation. Remarkably, for no individual peptide did a positive response for one T cell effector function correlate with any other. Thus these CS epitopes elicited unique T cell response patterns in malaria-exposed donors. Novel or important epitope responses may therefore be missed if only one T cell assay is employed. A borderline correlation was found between anti-CS Ab levels and proliferative responses, but no correlation was found with ex vivo or cultured IFN-gamma responses. This suggested that the proliferating population, but not the IFN-gamma-secreting cells, contained cells that provide help for Ab production. The data suggest that natural immunity to malaria is a complex function of T cell subgroups with different effector functions and has important implications for future studies of natural T cell immunity.

Publication

  • Journal: Journal of Immunology
  • Published: 15/10/2001
  • Volume: 167
  • Issue: 8
  • Pagination: 4729-4737