Table 3.

Reciprocal titers of neutralizing antibodies in chronic-phase serum from patients infected with HCV genotype 1a (H06) and 4a (AA) against JFH1-based viruses representing the six HCV genotypes

Envelope genotype	Reciprocal serum neutralizing antibody titer
	90%		50%
	1a (H06)	4a (AA)	1a (H06)	4a (AA)
1a	50	<50	1,600	50
2a	<50	<50	<50	<50
3a	<50	<50	<50	<50
4a	800	400	12,800	6,400
5a	3,200	800	25,600	3,200
6a	25,600	3,200	204,800	25,600

Approximately 100 TCID₅₀ of JFH1-based recombinant virus containing Core-NS2 of each of the six major genotypes was incubated in triplicates with a 2-fold dilution series of genotype 1a or 4a chronic-phase patient serum or a mixture of sera from four HCV negative controls and tested in Huh7.5 cells. Reciprocal neutralization titers are indicated as the highest dilution showing a reduction in FFUs of at least 90% or 50% compared to HCV-negative controls.