Visualization of carbohydrate-binding molecules expressed by myelomono- and erythropoietic cells derived from human...

Interactions between human haematopoietic and bone marrow stromal cells are governed by complex carbohydrate-mediated adhesion processes. In order to evaluate corresponding carbohydrate-binding sites on human myelo- and erythropoietic cells which were able to react with mono- or oligosaccharides, we established an immunocytochemical double-staining assay. In a first step, cell lineages were visualized using Lewis(x) (CD15) or glycophorin C-specific monoclonal antibodies. The second step included polyacrylamide-conjugated carbohydrate structures. According to our results, the carbohydrate-binding potential of granulopoietic cells increased during the process of maturation, contrasting a reduction of carbohydrate-binding sites on erythroid precursor cells during differentiation. With respect to previous in vitro studies, these findings shed some light on certain aspects of bone marrow homing as well as on the trafficking of mature cellular elements into circulation. It is tempting to speculate that carbohydrate-mediated adhesion mechanisms may be involved in the various functional defects of progenitor cells in chronic myelogenic leukaemia, especially regarding their complex interactions with the marrow microenvironment.