LYMPHOCYTE BLASTOGENESIS STUDIED BY VOLUME SPECTROSCOPY

The blastogenesis of human blood lymphocytes has been studied by measuring the distribution of cellular and nuclear volumes in concanavalin A (Con A)‐stimulated leucocyte cultures by means of a modified Coulter counter. Agglutinated and adherent cells wan dispersed by 3 h of incubation will α‐methyl‐mannoside and EDTA. Fresh suspensions contained 5‐35% monocytes with an average cellular volume 2‐2.5 times that of small lymphocytes. The nuclear volume of monocytes was similar to that of small lymphocytes within 10% and remained constant upon stimulation. In cultures given the optimal dose of Con A, 30 μg/ml. measurable cell growth commenced within 8‐12 h, whereas nuclear growth began some 6 h later, which is approximately 6‐8 h before increased 3H‐thymidine incorporation could he detected. The average volume of responding cells grew by a factor of about 4 until mitosis, which started after around 48 h. whereas the average nuclear volume increased by a factor of about 3. The percentage of cells responding by volume growth increased with mitogen concentration even for hyperoptimal concentrations (150μg/ml) which strongly suppressed 3H‐thymidine incorporation. The results exemplify the type of information obtained by volume spectroscopy of leucocyte cultures. This method appears to have several advantages over conventional assays of immune response. Copyright © 1979, Wiley Blackwell. All rights reserved