Light transmission analysis of lymphocyte activation by mitogens: a new technique

In vitro lymphocyte transformation was evaluated by laser light transmission cytometry. Criteria are given for optimal application of this system to assessment of total cells and proportion of lymphoblasts in cultures. The light transmission studies revealed that cell numbers in mitogen stimulated cultures increase steadily, reaching a plateau. The percentage of lymphoblasts reached a peak after 4 days culture. The kinetics of [3H]-thymidine incorporation are similar. The increase in total cell number concomitant with decrease in [3H]thymidine incorporation at the fifth and sixth days indicates discordance between the cell proliferation and utilization of exogenous thymidine. The kinetics of total cell numbers and percentage of lymphoblasts suggest that in vitro reversion of lymphoblasts to small lymphocytes occurred. In addition to examining directly the cellular events during blastogenesis with ease, the current method appeared to be more reproducible than the [3H]thymidine incorporation assay.