Counter-current distribution of red blood cells of different ages and from different species.

Abstract

Abstract Red blood cells from a number of different species were subjected to counter-current distribution in an aqueous, buffered dextran-polyethylene glycol, two-phase system. A marked correlation between the distribution of these cells and their relative electrophoretic mobilities was observed, leading to the conclusion that surface charge is a primary determinant in the behavior of cells on counter-current distribution. By injecting some of the animals with 59 Fe we were able to differentiate between young and old red cells in a given cell population. Counter-current distribution permits the separation of young and old cells not only from the rat (as we previously reported) but also from the dog, mouse and even chicken, leading to the conclusion that this is a general phenomenon. Sialic acid has been implicated as bearing almost the total surface charge of red blood cells. Analysis of the stroma from red blood cells of different ages ( i.e. , from cells in the different tubes of the extraction train after counter-current distribution) reveals that the sialic acid content is constant. However, the effective surface charge of red blood cells changes as a function of their age. This is most probably a consequence of the diminution of older red cells' surface 5 , and that their cell membranes become “altered” 14 . It is evidenced by the fact that older red cells can be electrophoretically separated from their younger counterparts 6 . This fact, together with the results obtained on counter-current distribution of red cells from different species, leads us to believe that a difference in surface charge is the primary determinant in the separation by counter-current distribution of red blood cells of different ages. An experiment demonstrating the effect of a different salt composition of the phase system used on the counter-current distribution of labeled red blood cells is also presented.