LEUKOSIALIN (CD43) BEHAVIOR DURING ADHESION OF HUMAN MONOCYTIC THP-1 CELLS TO RED-BLOOD-CELLS

To understand the modulation and the behavior of glycocalyx elements d uring adhesion, we explored one of its components, the CD43 molecule, on human monocytic THP-1 cells exposed to cytokine stimulation and its redistribution during heterotypic adhesion to opsonized erythrocytes, First we demonstrated by immunofluorescence and immunoprecipitation t hat CD43 is dys-sialylated in monocytic THP-1 cells stimulated by inte rferon-gamma (IFN-gamma) and tumor necrosis factor alpha (TNF-alpha) a nd stimulation increased correlated to heterotypic adhesion, CD43 anti -adhesive effect seemed to be related to sialic acid moeties because a n increase in adhesion was also induced by sialidase treatment and by monoclonal antibodies recognizing sialic acid-dependent epitopes on CD 43, Second, a redistribution of CD43 molecules was observed after adhe sion, resulting in the exclusion of CD43 molecules from contact areas as demonstrated by immunofluorescence and by ultrastructural immuno go ld localization, We therefore demonstrated in monocytic THP-1 cells th at some glycocalyx molecules can be modulated by cytokines and redistr ibuted during adhesion, These results support the concept that CD43 ca n regulate cell interactions.