BL21(DE3)LysS competent cells - (May/26/2010 )

I need to prepare BL21(DE3)LysS competent cells, for DH5 alpha I had never used antibiotics. Do for BL21(DE3)LysS I need to used antibiotic CM?????

Yes, the pLys plasmid has chloramphenicol resistance, and might be lost without selection.