TABLE 2.

Immunization with the p60 218F mutant does not stimulate p60 217–225-specific CTLs

Immunizationa	Effector CTL frequencyb
	LLO 91–99	p60 217–225	p60 449–457
Wild type	1/58,500	1/84,500	1/181,000
p60 218F mutant	1/52,900	NDc	<1/200,000
92F mutant	ND	1/93,480	<1/200,000

^aBALB/c mice were immunized with the indicated strains of L. monocytogenes. Six days later, spleen cells were stimulated in culture, and the recovered effectors were assessed for frequencies of peptide-specific CTLs. 

^b51Cr-labeled RMAS-K^d cells were pulsed with a 10⁻⁹ M concentration of the indicated peptide for 60 min and then added at 5 × 10³ cells/well. Serial dilutions of effector cells were added, and 4 to 6 h later, supernatant was collected for assay of ⁵¹Cr release. CTL frequency was determined as previously described (7). The data are representative of three experiments. 

^cND, not detected.