Table 2.

Immunologic response of volunteers immunized with a single 10³ PFU dose of the chimeric LGT/DEN4 vaccine candidate.

Volunteer ID#	Code	Serum neutralizing antibody titer on indicated day againsta:
		TBEV/DEN4Δ30				LGT
		0	28	42	180	0	28	42	180
02	Placebo	< 5	< 5	< 5	NTb	< 5	< 5	< 5	< 5
06	Placebo	< 5	< 5	< 5	< 5	< 5	< 5	< 5	< 5
12	Placebo	< 5	< 5	< 5	< 5	< 5	< 5	< 5	< 5
14	Placebo	< 5	< 5	< 5	< 5	< 5	< 5	< 5	< 5
16	Placebo	< 5	< 5	< 5	< 5	< 5	< 5	< 5	< 5
19	Placebo	< 5	< 5	< 5	< 5	< 5	< 5	< 5	< 5
25	Placebo	< 5	< 5	< 5	< 5	< 5	< 5	< 5	< 5
26	Placebo	< 5	< 5	< 5	< 5	< 5	< 5	< 5	< 5
01	Vaccine	< 5	14	9	< 5	< 5	300	404	101
03	Vaccine	< 5	< 5	< 5	12	< 5	10	20	< 5
04	Vaccine	< 5	23	8	33	< 5	210	97	175
05	Vaccine	< 5	318	164	186	< 5	3005	1702	283
08	Vaccine	< 5	9	6	18	< 5	43	27	41
09	Vaccine	< 5	< 5	7	10	< 5	35	25	11
10	Vaccine	< 5	< 5	< 5	< 5	< 5	18	11	5
11	Vaccine	< 5	11	8	25	< 5	250	119	25
13	Vaccine	< 5	< 5	< 5	< 5	< 5	41	26	30
15	Vaccine	< 5	< 5	< 5	27	< 5	54	64	65
17	Vaccine	< 5	< 5	< 5	< 5	< 5	< 5	< 5	15
18	Vaccine	< 5	< 5	< 5	< 5	< 5	90	75	< 5
20	Vaccine	< 5	< 5	< 5	< 5	< 5	< 5	< 5	< 5
21	Vaccine	< 5	5	5	NT	< 5	88	119	NT
22	Vaccine	< 5	< 5	< 5	< 5	< 5	67	47	< 5
23	Vaccine	< 5	21	304	276	< 5	145	833	217
24	Vaccine	< 5	30	48	175	< 5	264	516	45
27	Vaccine	< 5	8	5	9	< 5	55	33	8
28	Vaccine	< 5	< 5	< 5	6	< 5	< 5	6	< 5
29	Vaccine	< 5	16	25	131	< 5	1252	850	191
GMTc:			9	9	16		66	63	24
Seropositive:			10/20	11/20	12/19		17/20	18/20	14/19
			50%	55%	63%		85%	90%	74%
Seroconversion:			4/20	4/20	7/19		15/20	16/20	10/19
			20%	20%	37%		75%	80%	53%
			7/20 = 35%				16/20 = 80%

^aPlaque reduction (60%) neutralizing antibody titers (reciprocal) were determined against wild-type LGT TP21 strain or chimeric TBEV/DEN4Δ30 virus as indicated.

^bNT, not tested.

^cGMT, geometric mean titers (reciprocal) are calculated for all 20 vaccine recipients. For calculation of GMT, a negative titer (<1:5) was assigned a value of 4. Seroconversion (indicated by shading) is defined as a serum neutralizing antibody titer of ≥1:20 on study day 28, 42, or 180, compared with the pre-vaccination titer, which was <1:5 for each volunteer.