Table 3.
Functional activity of antiserum from mice immunized with outer membrane vesicle (OMV) vaccine prepared from Neisseria meningitidis RM1090 strain overexpressing GNA1870 variant 1 (v.1) protein after depletion of anti-GNA1870 antibodies.
| 1/antibody titer
|
|||
|---|---|---|---|
| Assay | Serum not absorbed | Serum absorbed with GNA1870 | Serum absorbed with NadA |
| Anti-GNA1870 ELISA | 40,000 | 400 | 30,000 |
| C3b complement deposition,a strain NZ98/254 | ≥400 | <25 | ≥400 |
| Bactericidal activity | |||
| Strain Cu385 | 2500 | <10 | 3000 |
| Strain M6190 | 1000 | 600 | 600 |
NOTE. A serum pool was prepared from mice immunized with OMV vaccine prepared from the RM1090 strain over-expressing GNA1870 v.1 protein. The antiserum was absorbed on a column containing recombinant GNA1870-HisTag protein or, as a negative control, recombinant NadA-HisTag protein [37], both of which were complexed with Ni-NTA Sepharose (Qiagen). The respective pass-through fractions were combined and concentrated to their original serum volume by membrane filtration.
Serum dilution in the flow-cytometric complement activation assay that elicited a 10-fold increase in immunofluorescence, compared with that for the negative control serum (see, e.g., figure 5).