TLR9 and infection: We found that TLR2 (Fig. 3E), TLR4 (Fig. 3F), TLR9 (Fig. 3G), and the TLR3/4 adaptor molecule TRIF (Fig. 3H) are dispensable for inducing host resistance against the subsequent infection, as observed by reduced bacterial loads in the lung of mice that were first infected with Lp thyA L. pneumophila compared to mock.