Ha. Giha et al., Nine-year longitudinal study of antibodies to variant antigens on the surface of Plasmodium falciparum-infected erythrocytes, INFEC IMMUN, 67(8), 1999, pp. 4092-4098
PfEMP1 is an antigenically variable molecule which mediates the adhesion of
parasitized erythrocytes to a variety of cell types and which is believed
to constitute an important target for naturally acquired protective immune
responses in malaria. For 9 years we have monitored individuals living in a
n area of low-intensity, seasonal, and unstable malaria transmission in eas
tern Sudan, and we have used this database to study the acquisition, specif
icity, and duration of the antibody response to variant parasitized erythro
cyte surface antigens. Both the levels and the spectrum of reactivity of th
ese antibodies varied considerably among individuals, ranging from low leve
ls of antibodies recognizing only few parasitized erythrocyte surface antig
ens to high levels of broad-specificity antibodies. In general, episodes of
clinical malaria were associated with increases in the levels of parasitiz
ed erythrocyte surface-specific antibodies that subsided within months of t
he attack This response was often, but not always, specific for the antigen
ic variants expressed by the parasite isolate causing disease. Our study pr
ovides evidence that Palciparum falciparum malaria is associated with a sho
rt-lived, variant-specific antibody response to PfEMP1-like antigens expose
d on the surface of parasitized erythrocytes. Furthermore, our data suggest
that the antigenic repertoires of variant antigens expressed by different
parasite isolates show considerable overlapping, at least under Sahelian co
nditions of low-intensity, seasonal, and unstable malaria transmission. Fin
ally, we demonstrate the existence of persistent differences among individu
als in the capacity to mount antibody responses to variant surface antigens
.