Effects of DEAE-dextran on the partition of red blood cells in aqueous dextran-polyethylene glycol two-phase systems

Abstract

Red blood cells of different ages and at least two populations of reticulocytes can be separated by countercurrent distribution in one of the buffered, aqueous two-phase systems containing dextran and polyethylene glycol. Rabbit red cells which are the most extensively studied in the current literature do not partition in these systems because of their low surface charge. We now report that the addition of small quantities of the cationic polymer DEAE-dextran to some of the previously used phase systems containing non-ionic polymers permits the distribution of low-charged cells (as exemplified by rabbit red cells). As a consequence we have been able to resolve rabbit red cells of different ages by countercurrent distribution. While dog red cells (which have a high surface charge) have larger partition coefficients than rabbit cells in phase systems with or without DEAE-dextran, we have found that a number of other generalities that apply to phase systems containing dextran and polyethylene glycol are reversed by the presence of DEAE-dextran. Thus, an increase in the salt ratio of NaCl/phosphate in a given phase system does not diminish the partition coefficients but instead increases them. The substitution of K + salts by Na + salts by Li + salts in the phase systems also no longer leads to an increase in the partition coefficients but rather to a diminution.