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.

Keywords

• hemocyte lectins
• hemagglutinins: β-galactosides
• phagocytosis
• opsonization
• hemocytes
• tunicates