Analysis of the lymphocyte distribution during Isopaque-Ficoll isolation of mononuclear cells from human peripheral blood.

Using chromium-labelled mononuclear cells the movements of lymphocytes in Isopaque-Ficoll (I-F) gradients were analysed. Even small percentages of ox or autologous human erythrocytes mixed with the lymphocytes caused a significant loss of lymphoid cells and this loss was augmented when higher numbers of red cells were added. Such losses could be prevented using I-F gradients of higher densities, but then neutrophils and erythrocytes were found to contaminate the mononuclear suspensions recovered. Purified B and T lymphocytes were found to move identically on the gradients, but when human erythrocytes were added to the lymphocyte suspensions to be separated, a small but significant preferential loss of T cells was observed.