TABLE 3.

Comparison of neutralizing antibody titers using prototype JEV (Nakayama) and ChimeriVax-JEV in PRNT₉₀

Specimen type (no. of samples)	Specimen no.	Neutralizing antibody titers in PRNT90a
		Prototype JEV Nakayama	ChimeriVax-JEV
JEV vaccinated (55)	1	1,280	1,280
	2	640	320
	3	640	1,280
	4 and 5	160	160
	6	160	320
	7	160	80
	8 and 9	160	40
	10 and 11	80	40
	12	40	40
	13	40	20
	14	20	20
	15 and 16	20	—
	17-20	40	10
	21-26	10	10
	27-55	—	—
JEV infection (14)	56	2,560	20,480
	57	5,120	10,240
	58	1,280	10,240
	59	2,560	5,120
	60	640	5,120
	61	640	2,560
	62	640	1,280
	63 and 64	320	1,280
	65 and 66	160	1,280
	67 and 68	640	640
	69	320	320
Other flavivirus infections (21)
DENV infection (9)	70-78	—	—
WNV infection (1)	79	—	—
YFV infection (3)	80-82	—	—
Past or secondary flavivirus infection (8)	83	320	640
	84	—	10
	85-90	—	—
All flavivirus negative (10)	91-99	—	—
	100	—	20
Positive control—JEV vaccine serumb		1,280	320
Negative controlc		—	—

^aThe neutralizing antibody titer is expressed as the reciprocal of the endpoint serum dilution that neutralized the challenge virus plaque count by 90%. LLOQ has a neutralizing antibody titer of 10; only positive titers (≥10) are shown. Dash = no detectable titer (<10).

^bMHIAF produced against JEV Nakayama strain.

^cNormal human control serum.