A longitudinal study of type-specific antibody responses to Plasmodium falciparum merozoite surface protein-1 in an area of unstable malaria in Sudan.

Abstract

Merozoite surface protein-1 (MSP-1) of Plasmodium falciparum is a malaria vaccine candidate Ag. Immunity to MSP-1 has been implicated in protection against infection in animal models. However, MSP-1 is a polymorphic protein and its immune recognition by humans following infection is not well understood. We have compared the immunogenicity of conserved and polymorphic regions of MSP-1, the specificity of Ab responses to a polymorphic region of the Ag, and the duration of these responses in Sudanese villagers intermittently exposed to P. falciparum infections. Recombinant Ags representing the conserved N terminus (Block 1), the conserved C terminus, and the three main types of the major polymorphic region (Block 2) of MSP-1 were used to determine the specificity and longitudinal patterns of IgG Ab responses to MSP-1 in individuals. Abs from 52 donors were assessed before, during, and after malaria transmission seasons for 4 yr. Ags from the Block 1 region were rarely recognized by any donor. Responses to the C-terminal Ag occurred in the majority of acutely infected individuals and thus were a reliable indicator of recent clinical infection. Ags from the polymorphic Block 2 region of MSP-1 were recognized by many, although not all individuals after clinical malaria infections. Responses to Block 2 were type specific and correlated with PCR typing of parasites present at the time of infection. Responses to all of these Ags declined within a few months of drug treatment and parasite clearance, indicating that naturally induced human Ab responses to MSP-1 are short lived.

• Authors: D R Cavanagh, I M Elhassan, C Roper, V J Robinson, H Giha, A A Holder, L Hviid, T G Theander, D E Arnot, J S McBride
• Journal: Journal of immunology (Baltimore, Md. : 1950) (J Immunol) Vol. 161 Issue 1 Pg. 347-59 (Jul 01 1998) ISSN: 0022-1767 [Print] United States
• PMID: 9647243 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Antibodies, Protozoan
• Merozoite Surface Protein 1
• Protein Precursors
• Protozoan Proteins

Topics

• Adolescent
• Adult
• Animals
• Antibodies, Protozoan (biosynthesis, blood)
• Antibody Specificity
• Antigenic Variation (genetics, immunology)
• Conserved Sequence
• Female
• Genotype
• Humans
• Longitudinal Studies
• Malaria, Falciparum (epidemiology, immunology, parasitology)
• Male
• Merozoite Surface Protein 1
• Molecular Sequence Data
• Plasmodium falciparum (genetics, immunology, isolation & purification)
• Polymorphism, Genetic
• Protein Precursors (immunology)
• Protozoan Proteins (immunology)
• Sudan (epidemiology)