A replica plating method for CHO cells using nylon cloth.

A new technique of replica plating for CHO cells has been developed in which the pattern of colonies growing in a tissue culture plate is reproduced on a nylon cloth. The efficiency of replica plating onto the nylon cloth is affected by the colony size and the time of cloth-to-plate contact. Maximum replica plating efficiency (80-90%) occurs using 5- to 6-day-old colonies and a contact time of 4 h. The method easily allows 10(4) colonies to be examined for mutant phenotypes. The effectiveness of the technique is demonstrated by isolation of a clone deficient in activity of glucose-6-phosphate dehydrogenase.