FIG. 3.
RIPA to show the specificities of anti-Ebola Zaire virus recombinant Fabs. (A) Immunoprecipitations are shown for Fab KZ51 (lanes 1 to 3), Fab ELZ510 (lanes 4 to 6), Fab KS14 (lanes 7 to 9), and convalescent-phase human serum (lanes 10 and 11). For reference, a [35S]Cys-[35S]Met-labeled virion preparation is shown in lane 12. The first lane shown for each Fab is the immunoprecipitate from [35S]Cys-[35S]Met-labeled Ebola virus-infected cell lysate, the second lane is from 35S-labeled crude Ebola virus supernatant, and the third lane is from 35S-labeled lysates from uninfected cells. KZ51 and ELZ510 precipitated NP (97 kDa) from 35S-labeled Ebola virus-infected cell lysate (lanes 1 and 4, respectively) and 35S-labeled crude Ebola virus supernatant (lanes 2 and 5, respectively). (B) Immunoprecipitations are shown for Fab KZ52 (lanes 1 to 3), Fab KS518 (lanes 4 to 6), and Fab LZ51 (lanes 7 to 9). For each Fab, immunoprecipitations are shown from [3H]glucosamine-labeled Ebola virus-infected cell lysate, 3H-labeled Ebola virus supernatants, and 3H-labeled uninfected cell lysates, respectively. KZ52, KS518, and LZ51 immunoprecipitated a band of 120 kDa corresponding to GP1 from [3H]glucosamine-labeled Ebola virus-infected cell lysate (lanes 1, 4, and 7, respectively). KZ52 also immunoprecipitated a band of 120 kDa from [3H]glucosamine-labeled Ebola virus supernatant (lane 2). The other two Fabs predominantly immunoprecipitated a band of 50 kDa, corresponding to sGP from this supernatant (lanes 5 and 8), with only a faint band at 120 kDa. (C) Longer-exposure autoradiograms obtained to reveal the immunoprecipitation of GP2. Exposure of autoradiograms for 2.5 months (compared to 1 week for panel B) reveals immunoprecipitation of a band corresponding to GP2 by Fabs KZ52, KS518, and LZ51 from Ebola virus-infected cell supernatants (lanes 1, 4, and 7, respectively) and from crude infected-cell supernatants (lanes 2, 5, and 8, respectively). Lanes 3, 6, and 9 are uninfected-cell supernatant controls.