[Separation of a rat thymocyte population in a ficoll-paque gradient. I. Relation of cell buoyant density to biological parameters].

Rat thymic cells were fractioned in the one-step Ficoll-Paque gradient. The three fractions obtained differed from one another with respect to average cell sizes, protein and DNA contents per cell. The light fraction cells revealed the maximum incorporation of labeled precursors into their nucleic acids, a relatively low hydrocortisone sensitivity and a diminished adhesion capacity. Following preincubation of thymus cell suspension and its gamma-irradiation, the number of the heavy fraction cells increased. The enrichment of the heavy fraction of cells with cortical thymocytes, including terminal ones, is supposed.