FIG. 11.

MAbs detect a conformational difference between L289A-F and the wt F protein. (A) Cells were transfected as follows: wt F, lanes 1, 5, and 9; L289A-F, lanes 2, 6, and 10; CSM F, lanes 3, 7, and 11; and CSM L289A-F, lanes 4, 8, and 12. Proteins were expressed in BHK cells driven by the vaccinia virus-T7 RNA polymerase expression system. Cells were starved for 1 h, labeled for 3 h, and chased for 90 min. Cells were lysed in Triton-deoxycholate. (A) Lanes 1 to 4, the F protein was immunoprecipitated with polyclonal rabbit anti-NDV serum; lanes 5 to 8, the F protein was immunoprecipitated with MAb Fa; lanes 9 to 12, the F protein was immunoprecipitated with MAb Fb. (B) An aliquot removed from each lysate before the addition of antibody was assayed by Western blotting to quantify cellular actin as a gel loading control.