A highly attenuated recombinant human respiratory syncytial virus lacking the G protein induces long-lasting protection in cotton rats

Table 2 Long term protection after a single dose immunization in cotton rats

Immunization^a	Challenge^b		Mean virus titers post challenge ± SD^c				Neutralizing antibodies at day of challenge (log₂)^d
			Lungs		Nose
Vaccine	Day	Virus	% positive animals	(log₁₀TCID₅₀/g)	% positive animals	(log₁₀TCID₅₀)
rRSV	70	RSV	0%	<2.1	17%	2.7	6.2
	142	RSV	0%	<2.1	33%	3.1 ± 0.5	4.9
ΔG	70	RSV	0%	<2.1	83%	3.7 ± 0.4	5.3
	142	RSV	0%	<2.1	83%	3.2 ± 0.7	4.2
mock	142	RSV	100%	5.0 ± 0.4	100%	3.8 ± 0.8	<3.3
mock	142	mock	0%	<2.1	0%	<1.6	<3.3

^a Cotton rats were infected with 10⁵ TCID₅₀ of the indicated virus at day 0. Groups consisted of 6 animals.
^b At the indicated days cotton rats were challenge i.n. with 10⁶ TCID₅₀ of RSV-X, and sacrificed 5 days post challenge.
^c Lungs and nasal washes were harvested and virus titers were determined. The lower limit of detection for virus in the lungs was 2.1 log₁₀TCID₅₀ g^-1 and in the nose 1.6 log₁₀TCID₅₀.
^d At the indicated days sera were collected and the neutralizing antibody titer against RSV-X was determined. The pre-infection serum titers were <3.3 (reciprocal log₂) for all animals in the study.

ISSN: 1743-422X