Combined prime-boost vaccination against tick-borne encephalitis (TBE) using a recombinant vaccinia virus and a bacterial plasmid both expressing TBE virus non-structural NS1 protein

Table 1 Protection of experimental animals against TBE virus in mice immunized with a vaccinia virus recombinant and a bacterial plasmid, both carrying the gene for the NS1 non-structural TBE virus protein

Group number	Primary immunization	Booster immunization	surviving/infected animals (% of survivers ± SE)
1	VV W-NS1	pMV45	8/10 (80 ± 13%)
2	VV W-NS1	pMV100	2/10 (20 ± 13%)
3	VV WR	pMV45	4/10 (40 ± 15%)
4	VV WR	pMV100	0/10 (0%)
5	None	None	0/10 (0%)

*- Balb/c mice were primed either with vaccinia viruses WR or W-NS1, boosted with bacterial plasmids pMV45 or pMV100 and challenged intraperitoneally with the TBE virus (Absettarov strain, 100 LD₅₀) as described in the Materials and Methods section. All the animals were monitored for 3 weeks after challenge with TBE virus. Standard error (SE) of a percent value was determined by the equation: SE = Square root of p × (100-p)/n, where p is a percent value and n is a number of animals used. Significance between two percent values (with probability 0.95): t = P1-P2/square root of SE1² + SE2² ≥ 2.0 [14].

ISSN: 1471-2180