Ultrastructure of Sickled Deer Erythrocytes. II. The Matchstick Cell

The matchstick cell is a unique form of sickled deer erythrocytes which is related to a specific β²-chain type in the white-tailed deer. Like the typical crescent form of sickled cell, it is an in vitro phenomenon which is induced by high pH and P_OO2 and reverses to the usual discoid form with deoxygenation and lowering of the pH. Transmission electron microscopy revealed a precise intracellular structure with polymerization of the hemoglobin into long filaments which were aligned in one axis of the cell, so that they appeared as long rods at relatively low magnification. A second feature, which contrasts to typical sickle forms of deer or man, is an absence of any type of microtubular structure. This suggests a different mode of intermolecular bonding related to primary structural variations of the β-chains which are associated with the matchstick cells and with typical sickle cells. Elucidation of the various structural differences between these β-chains may give additional clues to the mechanism of hemoglobin aggregation in the human sickle cell.