title: Stability of interferon-gamma and interleukin-10 responses to Plasmodium falciparum liver stage antigen-1 and thrombospondin-related adhesive protein in residents of a malaria holoendemic area.
abstract: The stability of anti-malarial immunity will influence the interpretation of immunologic endpoints during malaria vaccine trials conducted in endemic areas. Therefore, we evaluated cytokine responses to Plasmodium falciparum liver stage antigen-1 (LSA-1) and thrombospondin-related adhesive protein (TRAP) by Kenyans from a holoendemic area at a 9-month interval. The proportion of adults with interferon-gamma (IFN-gamma) responses to 9-mer LSA-1 peptides was similar at both time-points, whereas responses from children decreased (P < 0.05). Response to the longer, 23-mer LSA-1 peptide was variable, decreasing in adults and children over time (P < 0.02 and P < 0.001, respectively). The proportion of children with IFN-gamma responses to either antigen at the second time-point was significantly lower than that of adults, yet more adults responded to 9-mer TRAP peptides (P < 0.02). In contrast, the proportion of interleukin-10 responses to LSA-1 and TRAP was similar at both time-points for both age groups. Most noteworthy was that even when the repeat cross-sectional frequency of cytokine responses was the same, these responses were not generated by the same individuals. This suggests that cytokine responses to LSA-1 and TRAP are transient under natural exposure conditions.
authors.affiliation: Center for Global Health and Diseases, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106-7286, USA. moorms@case.edu
authors.forename: Ann M
authors.initials: AM
authors.lastname: Moormann
authors.forename: Chandy C
authors.initials: CC
authors.lastname: John
authors.forename: Peter Odada
authors.initials: PO
authors.lastname: Sumba
authors.forename: Daniel
authors.initials: D
authors.lastname: Tisch
authors.forename: Paula
authors.initials: P
authors.lastname: Embury
authors.forename: James W
authors.initials: JW
authors.lastname: Kazura
mesh_terms: D000293:Adolescent; D000328:Adult; D000818:Animals; D000953:Antigens, Protozoan / Q000276:immunology; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D019353:Endemic Diseases; D005260:Female; D006801:Humans; D007371:Interferon-gamma / Q000096:biosynthesis*; D016753:Interleukin-10 / Q000096:biosynthesis*; D007630:Kenya / Q000453:epidemiology; D017780:Malaria Vaccines; D016778:Malaria, Falciparum / Q000097:blood / Q000453:epidemiology / Q000517:prevention & control*; D008297:Male; D010963:Plasmodium falciparum / Q000276:immunology*; D015800:Protozoan Proteins / Q000276:immunology
chemical_list: D000953:Antigens, Protozoan; D017780:Malaria Vaccines; D015800:Protozoan Proteins; C067302:liver stage-specific antigen, Plasmodium; C069428:thrombospondin-related adhesive protein, protozoan; D016753:Interleukin-10; D007371:Interferon-gamma