Lectin-binding sites in the midgut of the mosquitoesAnopheles stephensi Liston andAedes aegypti L. (Diptera: Culicidae)

Abstract

The presence and distribution of binding sites for eight different lectins, Con A, DBA, HPL, LFA, RCA I, SBA, UEA I, and WGA, were compared in the midguts ofPlasmodium gallinaceum-infectedAedes aegypti andPlasmodium berghei-infectedAnopheles stephensi. Lectins with high specificity forN-acetyl-d-glucosamine (GlcNAc) exhibited high binding preference for the peritrophic membrane and microvillar glycocalyx ofAe. aegypti; the same structures were preferentially labeled byN-Acetyl-d-galactosamine (GalNAc)-specific lectins inAn. stephensi. No differences could be observed in the lectin-binding patterns of the intercellular spaces or cellular organelles and structures. ThePlasmodium ookinete surface did not react with any of the lectins tested. It appears that sugars are involved in vector recognition by the parasite and that the peritrophic membrane and/or glycocalyx may be crucial structures for the penetration of the gut epithelium by the ookinete.