Allele specificity of gamma interferon responses to the carboxyl-terminal region of Plasmodium falciparum merozoite surface protein 1 by Kenyan adults with naturally acquired immunity to malaria

UMMS Affiliation

Department of Quantitative Health Sciences; Department of Pediatrics

Publication Date


Document Type



Alleles; Animals; Cross-Sectional Studies; Gene Expression Regulation; Genotype; Humans; Immunologic Memory; Interferon-gamma; Kenya; Malaria, Falciparum; Merozoite Surface Protein 1; Peptide Library; Plasmodium falciparum; Seroepidemiologic Studies


Biostatistics | Epidemiology | Health Services Research | Immunology and Infectious Disease


Cross-sectional seroepidemiological studies of populations naturally exposed to Plasmodium falciparum suggest an association between protection from malaria and circulating antibodies to the carboxyl terminus of merozoite surface protein 1 (MSP1). Questions remain regarding the significance of cell-mediated immunity to MSP1 in conferring protection and inducing immunologic memory. Vaccine constructs have been based on the 42-kDa recombinant MSP1 protein (MSP1(42)), which includes the 19-kDa (MSP1(19)) and 33-kDa (MSP1(33)) fragments containing the major B- and T-cell epitopes, respectively. To evaluate T-cell responses to the MSP1(33) fragment, two libraries of overlapping 18-mer peptides from the 3D7 and FVO MSP1(33) regions were used to screen a cohort of asymptomatic Kenyan adults. Gamma interferon (IFN-gamma) measured by enzyme-linked immunospot assay (ELISPOT) at multiple time points assessed the magnitude and stability of these responses. The percentage of individuals with IFN-gamma responses to single MSP1(33) peptides ranged from nil to 24%, were clustered among a subset of peptides, and were not consistently recalled over time. In comparison to peptide responses, IFN-gamma ELISPOT responses to recombinant MSP1(42) were more prevalent, more frequently elicited by the 3D7 as opposed to the FVO allele, and more stable over time. The prevailing MSP1(33) genotype infection was 3D7, with few mixed infections and no sole FVO infections. This study demonstrates that immunity against MSP1(33) after cumulative natural infections consists of low-magnitude and difficult-to-detect IFN-gamma responses. Although immunity against MSP1 alone will not confer protection against malaria, demonstrating a relative and sustained increase in T-cell immunity to MSP1 after vaccination would be a reasonable measurement of vaccine responsiveness.

DOI of Published Version



Infect Immun. 2010 Oct;78(10):4431-41. Epub 2010 Aug 9. Link to article on publisher's site

Journal/Book/Conference Title

Infection and immunity

PubMed ID


Related Resources

Link to Article in PubMed