Table 1. Titers and infectivity of cys mutants.

	Titers (% change compared to wild-type ± SD)		Infectivity (% change compared to wild-type ± SD)		Infectivity Relative To L1 Protein (% change compared to wild-type ± SD)
Mutants	10-day	20-day	10-day	20-day	10-day	20-day
C428S	54%±14	8%±4	86%±24	64%±15	41%±28	5%±3
C175S	20%±15	1%±0.05	3.5%±1.2	46%±8	0.3%±0.2	0.1%±0.1
C185S	110%±30	13%±4	87%±7	152%±10	148%±60	20%±3
C175,185S	145%±51	14%±6	38%±7	31%±4	49%±26	10%±9