Ultrastructural localization of complex carbohydrates in rat monocytes and peritoneal and alveolar macrophages

Complex carbohydrates are demonstrated in lysosomes and other organelles of rat monocytes and macrophages by means of ultrastructural morphochemical techniques for localizing acidic groups and vicinal glycols that are characteristic of glycoconjugates. The presence of glycoconjugates in various cell organelles differ in monocytes and macrophages from different sites. Bone marrow and blood monocytes contained glycoproteins with periodate-reactive vicinal glycols, as shown by the periodate-thiocarbohydrazide-silver proteinate sequence in lysosomes, a population of small vesicular structures, and Golgi lamellae. However, these cells contained no dialyzed iron or high iron diamine reactivity indicative of acidic groups. Alveolar macrophages were similarly periodate-thiocarbohydrazide-silver proteinate-reactive, and contained a variable degree of dialyzed iron and high iron diamine reactivity demonstrative of acid mucosubstances in lysosomes. Peritoneal macrophages, on the other hand, exhibited highly reactive lysosomes with all three techniques, and revealed a population of periodate-thiocarbohydrazide-silver proteinate-positive vesicles not previously recognized and not readily discernable by other means. These cells also displayed periodate-thiocarbohydrazide-silver proteinate staining in large cisternal elements, possibly related to Golgi-endoplasmic reticulum-lysosome (GERL) and in other Golgi complex-related elements, as well as in cisternae of rough endoplasmic reticulum.