Ex vivo interferon-gamma immune response to thrombospondin-related adhesive protein in coastal Kenyans: Longevity and risk of Plasmodium falciparum infection

Katie L. Flanagan, Tabitha Mwangi, Magdalena Plebanski, Kennedy Odhiambo, Amanda Ross, Eric Sheu, Moses Kortok, Brett Lowe, Kevin Marsh, Adrian V S Hill

Research output: Contribution to journalArticleResearchpeer-review

35 Citations (Scopus)


Thrombospondin-related adhesive protein (TRAP) of Plasmodium falciparum is currently being tested in human vaccine studies. However, its natural reactivity in the field remains poorly characterized. More than 40% of 217 Kenyan donors responded in an ex vivo interferon-γ(IFN-γ) enzyme-linked immunospot (ELISPOT) assay to at least one of 14 20mer peptides spanning 42% of the antigen. Reactivity was comparable from early childhood (>1 year of age) to old age, and the maximal precursor frequency of TRAP-specific cells to all 14 peptides was 1 in 4,000. Prospective follow-up for one year indicated that these low-level ex vivo responses to TRAP did not protect against the subsequent development of malaria. Retesting of selected donors after one year showed a complete change in the reactivity pattern, suggesting that malaria-specific ex vivo IFN-γ ELISPOT assay responses are short lived in naturally exposed donors, even to conserved epitopes. This study provides important information regarding natural reactivity to a key malaria antigen.

Original languageEnglish
Pages (from-to)421-430
Number of pages10
JournalThe American Journal of Tropical Medicine and Hygiene
Issue number4
Publication statusPublished - Apr 2003
Externally publishedYes

Cite this