Analysis of Brugia pahangi microfilariae surface carbohydrates: comparison of the binding of a panel of fluoresceinated lectins to mature in vivo-derived and immature in utero-derived microfilariae.

A fluoresceinated lectin binding assay was employed to detect carbohydrates on the sheath and cuticle of mature in vivo-derived, and immature in utero-derived Brugia pahangi microfilariae. The sheath of mature microfilariae bound concanavalin A and wheat germ agglutinin, indicating the presence of N-acetylglucosamine and glucose or mannose. In addition to binding concanavalin A and wheat germ agglutinin, the sheath of in utero-derived microfilariae also bound Limulus polyphemus agglutinin, peanut agglutinin, Ricinus communis agglutinin-I, and soybean agglutinin, indicating the presence of the additional sugars galactose, sialic acid, and N-acetylgalactosamine. There was no evidence of cuticle carbohydrates, as none of the tested fluoresceinated lectins bound to either mature or immature exsheathed microfilariae. The significance of these results in terms of the survival of microfilariae in the mammalian host, and development to third-stage larvae in the mosquito vector, is discussed.