FIG 6.
Serum samples from mice immunized with LVS-V or Schu S4-V and challenged with live homologous bacteria detect similar bands by Western analysis but also exhibit differences in their binding specificities. (A) Mice were immunized either with LVS-V by two i.p. injections and challenged i.p. with F. tularensis LVS as described in Fig. 1 or immunized with Schu S4-V by i.p. and i.n. routes and challenged i.n. with F. tularensis Schu S4. Serum samples harvested 3 weeks postchallenge (LVS serum, 1:106; Schu S4 serum, 1:105) were used to probe Western blots (4 to 20% gradient gel) of vesicles (V, LVS-V, and Schu S4-V), whole-lysed bacteria (LVS and Schu S4), and purified recombinant F. tularensis proteins (DnaK and Tul4). (B) The same membrane at a lower (1-s) exposure to show DnaK and Tul4 detected by Schu S4-V-immunized/Schu S4-challenged survivor serum. Similar results were seen in two separate experiments.