Isolation of Human Lymphocytes by a Ficoll Barrier Method

Lymphocytes and polymorphonuclear granulocytes locate in Ficoll gradients at widely different densities. A method for the isolation of peripheral lymphocytes of human blood by centrifugation over a low‐ionic strength Ficoll barrier has been developed from this characteristic. The yields and serologic reactivities of lymphocytes isolated by the Ficoll method from normal human blood donors were comparable to those isolated by nylon‐column separation. However, the Ficoll method has been especially useful in preparing lymphocytes from blood of moribund individuals and others with an altered blood picture, where attempts on nylon columns failed to separate lymphocytes from polymorphonuclear granulocytes.