Separated hemocyte populations from the ascidian Ciona intestinalis contain and release in vitro opsonizing Ca2+-independent and β-galactoside specific lectins

Abstract

Cytosolic lectins, Ca2+-independent and β-galactoside-specific, were determined to be contained
in hemocyte and pharynx lysate supernatants of Ciona intestinalis, as revealed by hemagglutination
assay with trypsinized rabbit erythrocytes. Ca2+-independence and decreasing β-galactosides
inhibitory capacity (TDG > LacNAc ≥ Lactose > Galactose) have been considered properties typical of
galectins. These lectins can be promptly released by hemocytes maintained in vitro suggesting their
involvement in defense responses including inflammatory reactions. Both cell lysate supernatants and
hemocyte culture medium presented β-galactoside-inhibitable opsonizing activity versus yeast.
Although a Percoll density gradient separation method showed that several hemocyte types contain
and release β-galactoside-specific molecules, results suggest that hyaline and granular amoebocytes
are the primary source of these molecules.