| Abstract: | The relationship between membrane dynamics and cell growth in human leukemia-lymphoma cell lines of B, T or nonB-nonT phenotype was studied by fluorescence polarization (P) with the probe diphenylhexatriene. Cyclic variations in the degree of P were found as a function of time after subculture. The P value decreases within three hours, until a minimal value obtained before the phase of logarithmic growth. Then, P increases up to its presubculture value. The extent of these variations is not correlated to the differentiation phenotype of the cell lines, nor to their pathologic origin. Experiments with dialyzed or not depleted medium, show that these changes are seen only in the presence of fresh serum. Moreover, the P values vary with the ratio of serum concentration to cell number. These P value modulations are related to subsequent variations in proliferation rate, except in the immature non B-non T REH cells, which grow independently on the serum to cell ratio. It is concluded that changes in the dynamic organization of membrane components are specific for each cell line and are controlled by serum factors. |
