Figure 3
Sera against specific antigens promote C3 fragment deposition on NTHi. 176 strain was incubated with rabbit complement in the absence or presence of increasing amounts of sera from mice immunized with NTHi antigens or 176 strain heat inactivated. The amount of C3 deposited on bacteria (mean fluorescence) was measured by flow cytometry. Serum form mice given alum was used as negative control. Histogram tracings from one representative experiment for anti-176 serum are shown in addition to three of the antigens analyzed. RFI, relative fluorescence intensity.