Sialylation is modulated through maturation in hemocytes from Macrobrachium rosenbergii

In this work we identified in adult and juvenile freshwater prawn, Macrobra chium rosenbergii, three major type of circulating hemocytes: fusiform; rou nded; and large ovoid hemocytes. Rounded and large hemocytes represent the first defense line, since this type of cells exerts phagocytic activity as well as lectin synthesis. Considering that glycosylation plays important ro les in cell communication and as a target for pathogenic microorganisms, in this report was also described the main glycosidic modifications that occu r in the large and rounded hemocytes from the freshwater prawn during matur ation as determined with lectins. Neu5Ac alpha2,6Gal, was identified homoge neously distributed in the membrane in 90% of hemocytes from juvenile organ isms. Maturation of the freshwater prawn induced a decrease or complete los s of Neu5Ac alpha2,6Gal residues that were replaced with Neu5Aca2,3 molecul es in practically all hemocytes from adult organisms. This change was paral leled by a diminution in 9-O-acetyl-neuraminic acid (Neu5,9Ac(2)) expressio n. T and Tn antigens (Gal beta1,3 GalNAc alpha1-0-Ser/Thr or GalNAc alpha1- 0-Ser/-Thr, respectively), as well as N-glycosidically linked glycans, seem to be highly conserved throughout maturation. Our results show that sialyl ation of freshwater prawn hemocytes is modulated throughout the maturation process. (C) 2001 Elsevier Science Inc. All rights reserved.