Potency of a vaccine prepared from A/swine/Hokkaido/2/1981 (H1N1) against A/Narita/1/2009 (H1N1) pandemic influenza virus strain

Table 3 Neutralizing antibody titers of mice injected twice with the vaccine and virus titers in the lungs after challenge

Vaccine			NT titer to		Virus titer in lungs, mean log PFU/g ±Se^a
Strain	Protein, μg	Formulation	Narita/09	Sw/Hok/81
PBS	-	-	<10, <10, <10, <10, <10	<10, <10, <10, <10, <10	4.4±0.08
Sw/Hok/81	4.0	ES	<10, <10, <10, <10, <10	20, 40, 80, 160, 160	4.4±0.07
	20	ES	<10, <10, <10, <10, <10	80, 80, 160, 160, 160	4.2±0.19
	100	ES	<10, <10, <10, <10, <10	80, 80, 160, 320, 310	3.9±0.14*
Sw/Hok/81	4.0	WV	<10, <10, <10, <10, <10	160, 320, 320, 640, 640	4.2±0.11
	20	WV	<10, <10, <10, <10, <10	160, 320, 640, 640, 640	3.9±0.28
	100	WV	<10, 10, 40, 40, 160	160, 320, 640, 640, 640	2.9±0.30**

Mice were injected twice with each vaccine subcutaneously with a 2-week interval. Serum samples were collected 2 weeks after the final immunization.
The animals were challenged by intranasal administration of 106.0 PFU of A/Narita/09.
At 3 days after challenge, lungs samples were collected and virus titers were measured. ES: ether split vaccine, WV: whole inactivated vaccine
a: Data are for 5 mice.
*: P<0.05, vs. virus titers in PBS group.
**: P<0.01, vs. virus titers in PBS group.

ISSN: 1743-422X