Replica Plating and Detection of Antigen Variants

This chapter describes how to use polyester cloth to make replicas of Chinese hamster ovary (CHO) cell colonies and to process the replicas to screen for cells lacking a particular antigen. Same technique have been used for human HeLa S3 cells, mouse NIH 3T3, and Kirsten virus transformed NIH 3T3 cells and for monkey CV-1 cells. Each cell type has a different efficiency of replica plating but CHO cells give the best efficiency of replica formation. The chapter also illustrates the procedure for making replicas. Work in other laboratories using several other types of mammalian cells and a variety of methods for analyzing the replicas are described in the chapter. These groups used a variety of different cell lines and assay systems to isolate mutants. A few of the different cell lines and assay strategies that have been used successfully are described in the chapter for the general versatility of the technique. CHO cells appear to form the most reliable replicas and are very amenable to genetic manipulations. Another advantage of the CHO cells is the ability to make multiple high fidelity copies with the polyester.