Chemiluminescence and lymphocyte proliferation: parallelism in collaboration between subpopulations of thymus cells for both types of responses

Rat thymocytes respond to exposure to phytomitogens by oxidant generation as detected by chemiluminescence in presence of luminol. Maximal chemiluminescent response to a wide variety of plant lectins was obtained only after the cells had been incubated for 18 hours at 37 degrees C but not at 4 degrees C. This temperature dependence and the necessity for intact protein-and RNA-synthetic machinery during the incubation period indicate the occurrence of differentiation of thymocytes as they develop the capacity for chemiluminescent response. Furthermore, adherent-phagocytic cells play an essential collaborative role during this differentiation. A remarkable parallelism was shown to exist in the capacity of a cell subset to respond to concanavalin A by DNA synthesis and the ability of the same subset to respond by chemiluminescence. The latest-sedimenting small lymphocytes after velocity sedimentation of thymus cells develop the capacity for DNA-synthetic as well as chemiluminescent responses to concanavalin A only if allowed to collaborate with a population of early-sedimenting adherent-phagocytic cells.