TABLE 2.

Comparison of the frequencies of ex vivo LCMV-specific precursor CTL and of effector CTL after in vitro stimulation of spleens from mice immunized with the CyaA carrying multiple epitopes

In vivo immunizationa	Ex vivo CTL precursor frequencyb (no. of expts)	Effector CTL frequency after in vitro culturec (no. of expts)
CyaA wt-E5	NDd (3)	ND (3)
CyaA108MEP-E5	1/126,100 ± 1/39,120 (3)	1/4,667 ± 1/1,128 (3)
CyaA233MEP-E5	1/257,800 ± 1/179,800 (3)	1/3,495 ± 1/928 (3)
CyaA336MEP-E5	1/152,900 ± 1/33,870 (3)	1/9,073 ± 1/4,952 (3)
CyaA224LCMV-E5	1/282,000 ± 1/169,300 (3)	1/2,793 ± 1/177 (3)

^aBALB/c mice (two per group) were immunized i.p. on days 0 and 14 with 50 μg of recombinant CyaA toxoids mixed with 1 mg of alum. Control mice were immunized under the same conditions with detoxified wild-type CyaA. 

^bLCMV-specific precursor CTL frequencies were determined 7 days after the last injection by LDA, as described in Materials and Methods. Results are expressed as the mean ± standard error of the mean of the frequencies obtained in the different experiments. 

^cLCMV-specific effector CTL frequencies were determined after the 5-day in vitro stimulation by LDA as described in Materials and Methods. Results are expressed as the mean ± standard error of the mean of the frequencies obtained in the different experiments. 

^dND, not detectable.