The aim of this thesis is to examine quantitative and qualitative aspects of the serological immune response to MSP2 in a population of malaria-exposed individuals from West Africa. Recombinant MSP2 antigens, produced using pGEX plasmid expression vectors to direct the synthesis of MSP2 in Escherichia coli as fusions with glutathione S-transferase, were used to determine the presence of serum antibodies by enzyme-linked immunosorbent assay. The questions addressed in this thesis are whether MSP2 is immunogenic during natural infection with P.falciparum, whether amino acid polymorphism of MSP2 gives rise to antigenic polymorphism, and whether the immune recognition of MSP2 is variant-specific. In addition, the dynamics of acquisition of antibody to MSP2 with age, the IgG subclass specificity of anti-MSP2 antibodies and the association of MSP2-specific antibodies with protection against malaria infection have been investigated. MSP2 was found to be highly immunogenic, with high titre antibody present even in individuals known to have experienced only one episode of malaria. The antibody response is directed almost exclusively towards the dimorphic and polymorphic regions of MSP2 and antibodies to serogroups A and B do not cross-react. The acquisition of immunity to MSP2 is age-dependent, with the prevalence of anti-MSP2 antibodies and recognition of MSP2 variants increasing with age. Non-responsiveness does not appear to be genetically determined. Prospective longitudinal studies indicate that antibodies to MSP2 are associated with a reduced risk of clinical malaria. Qualitative differences in the antibody response were observed between children and adults; anti-MSP2 antibodies in adults are predominantly IgG3 whilst children also possess IgG1 antibodies. The expression of the IgG3 subclass increases with age among MSP2 seropositive individuals.