Table 1.

Viral titres in nasal washings of mice challenged with infectious Sendai virus

			Virus titre in nasal wash *
Immunization status	No. of mice (each strain)	Day of sacrifice post-challenge	C3HeB	BALB/c
Immunized	8	2	2·4 ± 1·5‡	3·3 ± 1·5‡
Immunized	8	4	2·2 ± 1·0‡	2·8 ± 0·7‡
Non-immune	8	2	3·6 ± 0·5§	5·1 ± 0·2
Non-immune	8	4	3·4 ± 0·4§	4·7 ± 0·4

^*Data are mean log pfu/ml lavage ± SD; no virus (i.e. titre < 1·4 in our assay) was detected in immunized (n = 8 per strain) or non-immune (n = 6 per strain) mice challenged with inactivated virus, or not challenged with intranasal virus.

^‡Different (F = 10·4, all t ≥ 2·2, all P < 0·05) from syngeneic nonimmune mice challenged with infectious virus and sacrificed on the same day post-challenge.

^§Different (all t ≥ 3·4, all P < 0·01) from the same treatment group in the BALB/c strain.