ANTIBODIES TO PF155/RESA AND CIRCUMSPOROZOITE PROTEIN OF PLASMODIUM-FALCIPARUM IN PAIRED MATERNAL-CORD SERA FROM NIGERIA

Paired maternal-cord serum samples were analysed for antibodies to the Pf155/RESA and circumsporozoite protein (CSP) antigens of Plasmodium falciparum. Malaria parasites were found in 2.6% (3/117) of cold blood and 22.4% (26/116) of maternal samples. Immunofluorescence assays detected P. falciparum-specific IgG antibodies in all paired samples while P. falciparum-specific IgM was detected in 5.8% (7/121) of cord samples. The positivity rates for antibodies to Pf155/ RESA and (NANP)(6) but not (EENV)(6), a C-terminal repeat sequence of Pf155/RESA, were significantly higher in maternal as compared with cord samples. Seropositivity rates to Pf155/RESA and (EENV)(6) were not related to maternal parity group while positivity rates to the (NANP)6 peptide were higher in primiparae and multiparae of greater than or equal to 4 parity. These data confirm the transplacental transfer of P. falciparum-specific antibodies and the higher incidence of malaria parasitaemia in primiparae. The presence of P. falciparum-specific IgM in some cord samples suggests intrauterine sensitization of the foetus to malarial antigens.