Table 1.

Different published helper phages

Helper phage name	Mutation/mechanism	aHelper phage titers/ml	Display levels	a,bRescued phagemid titers/ml	Use in display	Helper phage propagation	Reference
M13K07		1011c	Low	2 × 1010−12	Standard infection	Growth	(67)
KM13	Trypsin site in g3p, elution with trypsin	1011	Low	2 × 1010−12	Standard infection	Growth	(38)
	g3 deletion	105−6	High	∼1010	Standard infection	g3 plasmid expression under lac promoter	(68)
M13MDD3.2	g3 deletion	2 × 109	NT	109	Standard infection	g3p plasmid expression	(33)
R408d3	g3 deletiond	1010	NT	NT	Standard infection	g3p plasmid expression under pspA promoter	(27)
Hyperphage	g3 deletion (8-406)	109	High	109−10	Standard infection	g3p integrated into E.coli genome	(35)
CT helper phage	g3 N1 & N2 domains deletede	3 × 1011	Low	1011 total 5 × 108 infective	Standard infection	g3p plasmid expression	(37)
Ex-phage	Amber stop codon 5′ g3	1012−13f	High	1010−11	Non-suppressor strain	Suppressor strain	(36)
Phaberge	Amber stop codon 3′ g3	1011	High	109−10	Non-suppressor strain	Suppressor strain	(34)

The mechanisms of action, as well as the reported titers of both packaged phage and helper phage are given. NT-not tested.

^aTiters are unconcentrated supernatant titers—i.e. not PEG precipitated.

^bRefers to the number of infectious phagemid particles, independent of whether they carry antibody or no.

^cData from our laboratory.

^dSome reversion due to packaging of plasmid expressing p3 observed-probably also occurs in other plasmid expression systems, but not examined.

^eRescued phagemid are two populations, displaying and infective, non-displaying and non-infective.

^fStandard M13K07 titers obtained in this laboratory tend to be 10–100-fold higher than obtained elsewhere.