Scand. J. Immunol. 36, Suppl. 11. 17 22. 1992

Identification of Anii-Plasmodium falciparum Antibodies in Human Breast Milk R. G. F. LEKE. R. NDANSI. N. J. SOUTHERLAND, I. A. QUAKYI & D. W. TAYLOR* University Centre for Health Scieni:es. University of Yaounde, Yaounde. Canicroun. and *Department of Biology. Georgetown University. Washington. DC. USA

Leke RGF, Ndansi R. Southerland NJ. Qtinkyi lA, Taylor DW Ideniificulion of AnliFlasmodiumJaUiparum Antibodies in Human Breast Milk. Scand J Immunol l992;36(Suppl. 11); 17-22 Malarial infections are rarely observed in neonates. It has been postulated that some immunity may be passively transferred dtiring nursing, btii anti-malarial antibodies (Abs) have noi been delected m human milk. In this study, milk samples, collected 2 14 days after parturition from women ill the Central Maternity Hospital, Yaounde, were evaluated for toial IgG and IgA anlibody levels by radial diffusion, protein comptxsition by SDS PA(iE. anli-maiarial antibodies using an isoiypc-specific immunofluorescenee assay, and the ability m immunoprecipitate /'/avm(«//H»iy(j/(-i/>«rM»ranligensmetaboiically labelled with '^S-methionine. ResulIs showed that anti-^./«/n/Ji;ru/Hanliboifies were present in breast milk, and ihal paired milk and serum samples from individual women contained Abs that recognized similar mularial antigens. Diane W. Tavlor. Departmenl of Biology. Georgetown University. J7th A O Streets NW, Washingiun. DC 20057-1028. USA

Children living In areas with endemic malaria rarely acquire infections prior to .1-6 months of age. This observation was confirmed in 1977 by E. Dame in a study conducted in Yaounde. Camcroun [1]- A tola! of 232 children < I year of age were examined. Although 5.2% were found to be slide-positive for malaria, none of ihc children fl3 months of age were infected. The reason for this is not clear but lack of parasitaemia and clinical malaria in newboms has been atlributed to (I) antibodies (Abs) acquired transplacentally. (2) presence of felal haemoglobin. (3) decreased number of mosquito bites. (4) lack of paraminobenzoic acid (PABA) in a completely milk diet, and (5) potentially Abs acquired through nursing. This study sought to determine if mothers possessed anti-P. falciparum Abs in their milk and, if so. to characteri:^ the antigenie specificity of such Abs.

MATERIALS AND METHODS Clinical samples. P. falciparum malaria is transmitted throughout the year in Cameroun. with peak transmission following the two rainy seasons. Women included

in this study have been exposed to malaria thruughoul iheir lives. Samples were collected in June July 1990. a period immedialely atier Ihe rainy season when Ab levels should be high. Paired plasma and milk samples were collected from 22 women, age 17 .13 years. 2 14 days after delivery. Samples were frozen at - 2 0 " C until assayed. Equivalent milk samples were colleeted in the United Stales. Four of ihe controls were selected because ihey had grown up in developing countries but had resided in the United Slates for > I year prior to delivery; Ihe olhers had resided in the United Stales throughout their lives. Controls included women of Black. Oriental and Caucasian ancestry. Quantiiation nf immunof-tohulin Urels in hreast milk. Milk samples, used either undiluted or diluted 1:2 in 0.1 M phosphate-buffered saline. pH 7.2 (PBS), were applied to wells of quan-plales containing antisera specific for human IgG. IgA and IgM (Kallestad Labs, Austin. TX). The diameters of the tesl samples were compared with the standards provided in the kits and concentrations were determined from a standard curve according lo the manufacturer's directions. IJentificaiion ufaniitnaUirial Abs hy indirect immunnftuorescence Various dilutions of milk were applied to acetone-fixed blooil smears of in vitro cultured P. falciparum piirasilc^s. Slides were incubated for 20 min, washed wiih PBS and rabbil antisera to human ot. y. and f.1 (Cappel. West Chester. PA) were applied. After incubation for 20 min. slides were washed and FITClabelled goat anti-rabbit Ig (Calbiochcm Corp.. La 17

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R. G. F. Leke et ai.

Jolla, CA) was added. Slides were mounlcd in O.I M barbital bufTcr (pH t

Identification of anti-Plasmodium falciparum antibodies in human breast milk.

Malarial infections are rarely observed in neonates. It has been postulated that some immunity may be passively transferred during nursing, but anti-m...
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