Malaria and pregnancy in Cameroonian women. Naturally acquired antibody responses to asexual blood-stage antigens and the circumsporozoite protein of Plasmodium falciparum

Abstract

Antibody responses to Plasmodium falciparum antigens in women during pregnancy were investigated in Mfou, a rural community in Cameroon. The study consisted of cross-sectional analyses involving 225 pregnant women and 75 non-pregnant controls. Blood samples were collected from each woman to determine serological reactivity to intraerythrocytic malarial antigens, ring-infected erythrocyte surface antigen ( resa) and circumsporozoite (CS) repeat peptide (NANP) 5 by the indirect fluorescent antibody assay, modified immunofluorescent antibody assay, and enzyme-linked immunosorbent assay, respectively. Reactivity to intraerythrocytic asexual blood-stage antigens and to the CS repeat region was similar in both pregnant and non-pregnant women, and no correlation with parasitaemia was found. In contrast, anti- resa antibody levels were significantly lower in pregnant than in non-pregnant women ( P = 0·02) and in primigravidae than in multigravidae ( P = 0·002), and were inversely correlated with parasitaemia ( r = −0·36; P < 0·01). These data suggest that the increased susceptibility to malarial infection in pregnant women may be explained in part by their lower reactivity to resa.