Studies on cellular adhesion in tissue culture: XIV. Positively charged surface groups and the rate of cell adhesion

Abstract

Attempts were made to identify positively charged groups at the surfaces of Ehrlich ascites tumour (EAT) cells, and particles of polystyrene polymer which had adsorbed proteins after incubation in serum-containing culture medium. The cells and particles were treated with 2,4,6-trinitrobenzene sulphonic acid (TNBS) or 2,3-dimethylmaleic anhydride (DMA), which react with amino and other cationic groups. The increases in cell and particle anodic electrophoretic mobility were consistent with approx. 5% of the total surface charge of each, being due to positively charged groups. The effects of DMA or TNBS treatment of the cells and/or polystyrene surfaces, on the rates of cell adhesion to these surfaces were then determined. The significantly slower rates of adhesion after some modes of treatment suggest that positively charged groups at the surfaces of EAT cells play a part in their initial contact with and adhesion to, protein-coated plastic surfaces. However, quantitatively the role of cationic groups is a minor one in this part of the adhesion process.