Table 3

Replication and immunogenicity of rDEN1/4 chimeric viruses in rhesus monkeys.

Virus1
No. of monkeys
% of monkeys with viremia
Mean no. of viremic days per monkey
Mean peak virus titer2 (log10 PFU/ml ± SE)
Geometric mean serum neutralizing antibody titer (reciprocal dilution)3
Post-challenge5












Day 0
Day 28
% sero-conversion4
% of monkeys with viremia
Mean peak virus titer2 (log10 PFU/ml ± SE)

DEN1 Puerto Rico/94
4
100
2.8
2.0 ± 0.1
< 5
103
100
0
< 1.0
rDEN1/4 (CME)
4
100
2.0
1.5 ± 0.1
< 5
56
100
0
< 1.0
rDEN1/4Δ30 (CME)
4
50
0.5
1.1 ± 0.1
< 5
< 5
0
75
1.7 ± 0.3
rDEN1/4 (ME)
4
100
4.0
2.1 ± 0.1
< 5
65
100
0
< 1.0
rDEN1/4Δ30 (ME)
6
50
0.7
1.1 ± 0.2
< 5
23
66
0
< 1.0
Mock infected
2
0
0
< 1.0
< 5
< 5
0
100
2.1 ± 0.2

1 Groups of rhesus monkeys were inoculated subcutaneously on day 0 with 5.0 log10 PFU of the indicated virus in a 1 ml dose. Serum was collected daily for 10 days to detect viremia and on day 28 for determination of neutralizing antibodies.

2 Virus titer in serum was determined by plaque assay in Vero cells.

3 Plaque reduction (60%) neutralizing antibody titers were determined using DEN1 Puerto Rico/94 as test virus.

4 Percentage of monkeys with a four-fold or greater rise in neutralizing antibody levels between day 0 and 28.

5 Monkeys were challenged after 35 days with DEN1 (Puerto Rico/94) administered subcutaneously in a 1 ml dose containing 5.0 log10 PFU. Serum was collected daily for 10 days to detect viremia.

Blaney et al. Virology Journal 2007 4:23   doi:10.1186/1743-422X-4-23