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. 2014 Jul;88(14):8139–8152. doi: 10.1128/JVI.00425-14

TABLE 6.

Immunogenicity and protective efficacy of H6N1 and H9N2 ca vaccines in AGMsa

Vaccine/no. of doses Challenge virus AGM no.b Serum Ab response
 Titer of challenge virus in respiratory tissues(log10 TCID50/g)
 Titer of challenge virus in swabs and lavage fluid(log10 TCID50/ml)
HAIc
 MNd
 Nasal turbinates Trachea Lung Nasal swab Pharyngeal swab Tracheal lavage fluid
Day 42 Day 58e Day 42 Day 58e
Mock/1 H6N1 wt H6-M 1 <20 <20 <10 <10 ≤1.5 2.5 2.8 ≤0.5 ≤0.5 1.0
H6-M 2 <20 <20 <10 <10 5.2 4.7 3.7 4.0 ≤0.5 1.0
H6-M 3 <20 <20 <10 <10 5.4 6.7 3.6 4.2 2.7 3.2
H6-M 4 <20 <20 <10 <10 3.7 3.6 3.6 3.4 ≤0.5 3.0
H6N1 ca/1 H6N1 wt H6-1D 1 40 20 50 50 ≤1.5 ≤1.5 ≤1.5 3.2 ≤0.5 ≤0.5
H6-1D 2 80 40 50 226 ≤1.5 ≤1.5 ≤1.5 ≤0.5 ≤0.5 ≤0.5
H6-1D 3 <20 <20 28 <10 ≤1.5 ≤1.5 ≤1.5 ≤0.5 ≤0.5 ≤0.5
H6-1D 4 <20 <20 32 25 ≤1.5 ≤1.5 ≤1.5 ≤0.5 ≤0.5 ≤0.5
H6N1 ca/2 H6N1 wt H6-2D 1 1280 1280 2560 1016 ≤1.5 ≤1.5 ≤1.5 ≤0.5 ≤0.5 ≤0.5
H6-2D 2 160 160 453 254 ≤1.5 ≤1.5 ≤1.5 ≤0.5 ≤0.5 ≤0.5
H6-2D 3 320 160 905 453 ≤1.5 ≤1.5 ≤1.5 ≤0.5 ≤0.5 ≤0.5
H6-2D 4 1280 640 2560 1280 ≤1.5 2 ≤1.5 ≤0.5 ≤0.5 ≤0.5
Mock/1 H9N2 wt H9-M 1 <20 <20 <10 <10 ≤1.5 5.2 2.4 1.0 1.0 2.7
H9-M 2 <20 <20 <10 <10 ≤1.5 2.5 3.0 ≤0.5 ≤0.5 1.0
H9-M 3 <20 <20 <10 <10 6.0 2.0 3.6 3.2 1.0 3.4
H9-M 4 <20 <20 <10 <10 ≤1.5 4.0 3.4 ≤0.5 2.4 4.0
H9N2 ca/1 H9N2 wt H9-1D 1 <20 <20 50 32 ≤1.5 ≤1.5 1.6 ≤0.5 ≤0.5 ≤0.5
H9-1D 2 <20 <20 25 28 ≤1.5 ≤1.5 2.3 ≤0.5 ≤0.5 ≤0.5
H9-1D 3 80 40 403 80 ≤1.5 ≤1.5 ≤1.5 ≤0.5 ≤0.5 ≤0.5
H9-1D 4 80 40 113 113 ≤1.5 ≤1.5 ≤1.5 ≤0.5 ≤0.5 ≤0.5
H9N2 ca/2 H9N2 wt H9-2D 1 640 640 403 1016 ≤1.5 ≤1.5 ≤1.5 ≤0.5 ≤0.5 ≤0.5
H9-2D 2 160 80 320 101 ≤1.5 ≤1.5 ≤1.5 ≤0.5 ≤0.5 ≤0.5
H9-2D 3 320 160 901 160 ≤1.5 ≤1.5 ≤1.5 ≤0.5 ≤0.5 ≤0.5
H9-2D 4 160 80 453 113 ≤1.5 ≤1.5 ≤1.5 ≤0.5 ≤0.5 ≤0.5
a

ca, cold adapted.

b

AGM numbers are expressed as follows: subtype of vaccine (H6, H6N1 ca vaccine; H9, H9N2 ca vaccine)-number of doses (1D, one dose; 2D, two doses; M, mock [L15 medium]) followed by animal identification number.

c

The HAI assay was performed using 1% horse red blood cells for H6N1 virus and 0.5% turkey blood cells for H9N2 virus, and titers are expressed as the highest dilution of serum that inhibited agglutination of 8 HAU of virus. The lower limit of detection was 20. Antibody titers from individual animals are listed.

d

MN titers are expressed as the serum dilution that inhibited infectivity of 100 TCID50 of virus in a microneutralization assay using MDCK cells. The lower limit of detection was 10. Antibody titers from individual animals are listed.

e

AGMs were challenged on day 56 with wt viruses, and tissues and secretions were collected from AGMs 2 days after the challenge infection (day 58). The lower limit of detection of virus in tissues was 1.5 log10 TCID50/g and in swab and lavage fluid was 0.5 log10 TCID50/ml.