TABLE 3.

Hemagglutination-inhibitory activity against Pan/99 virus of sera from guinea pigs immunized with inactivated Pan/99 vaccine

Treatment and guinea pig	Vaccined	Route of challengec	Titer
			Preimmune	Postvaccinatione	Postchallengef
Killed vaccine, homologous challengea
23	PBS	Inoculation i.n.	<10	<10	320
24	PBS	Inoculation i.n.	<10	<10	160
25	PBS	Exposure	<10	<10	40
26	PBS	Exposure	<10	<10	160
27	iPan/99	Inoculation i.n.	<10	640	1,280
28	iPan/99	Inoculation i.n.	<10	320	1,280
29	iPan/99	Inoculation i.n.	<10	320	640
30	iPan/99	Inoculation i.n.	<10	320	320
31	iPan/99	Exposure	<10	640	640
32	iPan/99	Exposure	<10	320	1,280
33	iPan/99	Exposure	<10	320	ND
34	iPan/99	Exposure	<10	320	640
Killed vaccine, heterologous challengeb
35	PBS	Inoculation i.n.	10	10	10
36	PBS	Inoculation i.n.	10	10	10
37	PBS	Exposure	10	10	10
38	PBS	Exposure	<10	20	640
39	iPan/99	Inoculation i.n.	10	5,120	5,120
40	iPan/99	Inoculation i.n.	10	640	1,280
41	iPan/99	Inoculation i.n.	10	2,560	2,560
42	iPan/99	Inoculation i.n.	<10	640	1,280
43	iPan/99	Exposure	10	1,280	1,280
44	iPan/99	Exposure	<10	1,280	2,560
45	iPan/99	Exposure	10	1,280	2,560
46	iPan/99	Exposure	10	1,280	2,560

^aSee Fig. 4.

^bSee Fig. 5.

^ci.n., intranasally.

^diPan/99, inactivated Pan/99 virus.

^ePostvaccination blood samples were collected 42 days after the initial vaccination dose was given.

^fPostchallenge blood samples were collected on day 18 or 19 after challenge. ND, not done.