Download Glycoconjugate expression in the immune response of the marine

Glycoconjugate expression in the immune response of the marine sponge, Microciona prolifera
Halle E. Burns, Pablo Tovar, Selsebil Sljivo, Courtney W. Sullivan, and Ellen E. Faszewski
Wheelock College, Department of Math and Science, Boston, MA
Carbohydrate components of glycoconjugates have many cellular functions including adhesion, differentiation,
membrane permeability, and intercellular recognition. Previous research in sponges has also identified their
role in the immune response (e.g., prevent adhesion of bacteria and fungi to cellular surfaces). Microciona
prolifera, the red beard sponge, is able to distinguish self-vs nonself by forming a barrier zone, referred to as
the zone of contact (ZOC), if an individual comes into contact with a different individual. The ZOC is comprised
of cells undergoing programmed cell death (apoptosis). The purpose of this project was to examine the
localization four sugars, β-galactose (Gal), N-Acetyl-Galactosamine (GalNAc), α-L-fucose (Fuc), and N-AcetylGlucosamine (GlcNAc), in the process of apoptosis and their corresponding relationship to self-vs-nonself
recognition. Cross sections of sponge tissue, 0, 2, 4, 6, 12, and 48 hours after grafting, were stained with the
following lectins: peanut agglutinin (PNA), soybean agglutinin (SBA), Ulex europaeus agglutinin (UEA), and
wheat germ agglutinin (WGA). Two negative controls were used: 1) phosphate buffered saline (PBS), and 2) the
pre-incubation of each lectin with 0.2M of its inhibitory sugar. Results indicate that while many cells in the
mesohyl stained with PNA, indicative of Gal, SBA, indicative of GalNAc, and UEA, indicative of Fuc, very few
positive cells were observed in the ZOC. On the other hand, WGA staining, identifying GlcNAc, was not present
in either location; however, WGA staining was observed in epithelial cells. These results indicate that while all
four sugars are present in M. prolifera, their limited expression in the ZOC suggests their minimal role in self vs.
nonself recognition.