Surface properties of normal human circulating small lymphocytes and lymphocytes in chronic lymphocytic leukaemia: Separation, adhesiveness and electrokinetic properties

Abstract

1. ( 1) In the absence of serum, lymphocytes from patients with chronic lymphocytic leukaemia (C.L.L. lymphocytes) behaved like lymphocytes from healthy individuals (normal lymphocytes) by adhering to columns of polystyrene beads at 37°C and/or at 4°C. Two-thirds or more of the abnormal (colchicine-ultrasensitive) cells contained in the populations isolated from 4 of the 13 patients ( 2 treated, 2 untreated) displayed further abnormality by adhering in the presence of serum at 37°C and are termed ‘adhesive abnormal cells’. This type of adhesiveness could be abolished by treatment with trypsin or, reversibly, by operating columns at 4°C, and it is suggested that it reflected motile behaviour different to normal cells. 2. ( 2) The results of one experiment suggest the future trial of reduced serum concentrations, leading to higher retention of abnormal cells on polystyrene beads, as a means of obtaining ostensibly-normal (colchicine-resistant) members of C.L.L. lymphocyte populations for separate study. Desorption of normal small lymphocytes from protein-free columns with the aid of serum is recommended for trial as a possible means of subfractionating normal populations into different functional types. 3. ( 3) The lymphocytes which had been isolated in different ways from the blood samples (normal donors and 7 C.L.L. patients; 4 treated, 3 untreated) washed twice in the standard saline ( 0·145 m NaCl; pH: 7·2±0·2) and resuspended in saline were observed to have average electrophoretic mobility values of −1·09±0·08 μ/sec./V/cm. No effects upon electrophoretic mobility were noted from the use of heparin ( 2·5 units per ml. of blood) as anticoagulant, or after exposing lymphocytes to NH 4 Cl or hypotonic shock treatment in order to remove residual red cells. With one exception, no differences were noted between the mobilities of normal lymphocytes and C.L.L. lymphocytes, or C.L.L. lymphocytes from different patients, despite variations in clinical, haematological and therapeutic status, and despite the presence of contrasting proportions of adhesive abnormal cells in the different populations. 4. ( 4) The pH-mobility relationships for 4 C.L.L. patients were established and suggest that the electrokinetic behaviour of the lymphocytes arises as a result of the presence of several ionizable (acidic and basic) groups on the surface of adhesive abnormal and non-adhesive abnormal cells. The pK of one acidic group is estimated to be 3 and it is probably due to a sialic acid carboxyl group. The basic groups are probably amino and/or sulphydryl with a pK of 10·5 and from one experiment these would appear to be present also on the surface of the normal small lymphocyte.