Abstract
The concanavalin A-gold labeled horseradish peroxidase (Con A-HRP-G) method has been employed in the ultrastructural localization of Con A surface receptor sites on glutaraldehyde-fixed normal human and guinea pig bone marrow cells. The number of gold particles per micron of cell surface was counted and data subjected to statistical analysis. All cells of the bone marrow exhibited Con A binding; however, the extent of surface labeling was dependent both on cell type and stage of differentiation. Distinctive modifications in mean surface density correlated with specific periods during the maturation of the erythrocytic, neutrophilic, eosinophilic and monocytic cell series. In several instances, the differentiative changes in surface Con A labeling proved to be species dependent. These observations are discussed in relationship to methodology and to potential changes in number and/or spatial arrangement of Con A receptor sites, primarily attributable to mannosyl and/or glucosyl residues associated with membrane glycoproteins and/or glycolipids of developing neutrophilic and erythrocytic cells.