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

Journal article

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-gamma (IFN-gamma) 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-gamma 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.

Authors: Flanagan, K; Mwangi, T; Plebanski, M; Odhiambo, K; Ross, A

• Publication status: Published
• Journal: American journal of tropical medicine and hygiene
• Volume: 68
• Issue: 4
• Pages: 421-430
• Publication date: 2003-04-01
• EISSN: 1476-1645
• ISSN: 0002-9637
• Language: English
• Keywords: Peptide Fragments; Risk Factors; Female; Malaria, Falciparum; Aged; Kenya; Middle Aged; Humans; Infant; Aged, 80 and over; Adolescent; Molecular Sequence Data; Male; Pilot Projects; Enzyme-Linked Immunosorbent Assay; Amino Acid Sequence; Longevity; Child; Immunity, Cellular; Protozoan Proteins; Leukocytes, Mononuclear; Malaria Vaccines; T-Lymphocytes; Adult; Child, Preschool; Interferon-gamma