Figure 1. Heterosubtypic cross-protection induced by WIV depends on TLR7 activation.

Wt and TLR7−/− mice were either vaccinated twice (on days 0 and 21) subcutaneously (s.c.) with 20 µg of H5N1 WIV or similarly mock-vaccinated with HNE buffer. A lethal heterosubtypic challenge with H1N1 virus was administered one week later. (A) After challenge, mice were monitored daily over a period of 14 days for body weight change. Body weight loss of more than 20% was an indication for euthanasia (dashed line). (B) Virus titers in the lungs of wt (black bars) and TLR7−/− (white bars) mice were measured 6 days post-challenge. Bars represent mean±SEM of 3 mice per group. *p<0.05; Mann-Whitney U-test.