Rapid Enumeration of S-Phase Cells by Means of Monoclonal Antibodies

Abstract
To the Editor: We report a rapid technique for estimating the amount of S-phase cells in a sample with use of monoclonal antibodies (RPMB I through VI) directed against bromdeoxyuridine. Cells (1X107 per milliliter) are incubated with 10-4 M bromdeoxyuridine in the presence of 10-5 M fluorodeoxyuridine for 30 minutes, so that any cell in S-phase will incorporate bromdeoxyuridine in place of thymidine in its DNA. Three drops of this suspension are gently pipetted on coverslips coated with Alcian blue. The adherent cells are treated with 70 per cent ethanol to allow materials to permeate the cell membranes. After hydrochloric . . .