Table I.

Mice without Ig can be protected against influenza challenge infection by prior exposurea

Priming VirusChallenge VirusMean Log10 Lung Virus, TCID50/gm Tissue (No. of Mice with Undetectable Lung Virus/Total Mice)
DI Day 5DI Day 7B6 Day 5B6 Day 7
B/AAB/AA1.6 ± 0.1b1.8 ± 0.4c1.5 ± 0b1.5 ± 0b
(5/6)(4/6)(4/4)(5/5)
A/UdornB/AA4.5 ± 0.52.0 ± 0.2c5.0 ± 0.43.7 ± 0.4
(0/6)(3/7)(0/5)(0/5)
PBSB/AA3.4 ± 0.53.4 ± 0.45.2 ± 0.23.7 ± 0.6
(2/8)(1/7)(0/5)(0/5)
  • a Mice were primed with 5 × 103 TCID50 units per mouse of flu B/AA or A/Udorn or were given 50 μl of PBS i.n. They were challenged on day 32 with B/AA, 104 TCID50 units per mouse. On day 5 or 7 postchallenge, lungs were harvested and analyzed for virus titers. Geometric means ± SE were calculated using the value 1.5 for ≤1.5 (i.e., no detectable virus). Below mean titers in parentheses are ratios of the number of mice with undetectable lung virus/total number of mice.

  • b Significantly different from PBS group in the same column; p < 0.01. Values of ≤1.5 were entered as 1.5 for the purpose of t tests.

  • c Significantly different from PBS group in the same column; p < 0.03.