TABLE 1.

AVA vaccination histories of the human subjects and LF-to-EF ratios of antibody responses and neutralization titers

Sample	Total no. of inoculations	No. of mos since last inoculation	Antibody response ratio, LF/EFa	Neutralization ratio, LF/EFb
S1	6	30	0.7	2.0
S2	6	16	0.6	1.0
S3	5	12	2.3	0.5
S4	5	12	0.3	2.0
S5	4	6	0.3	1.0
S6	5	9	11.8	1.0
S7	5	1	3.6	1.0
S8	5	12	1.3	0.5
Pool	0	NAc	NRd	NA

^aSerum sample reactivity to PA, LF, or EF proteins was detected by Western blotting. Band intensity was quantified, and the ratio of LF antibody response to EF antibody response was calculated.

^bRatio of titers determined by comparing antibody-mediated neutralization of LF-induced lysis to neutralization of EF-induced cAMP increases.

^cNA, not applicable.

^dNR, not reactive.