TABLE 5.
Bactericidal titers of rabbit IgG elicited with wild-type or point-mutated MBP-TbpB R243N toward a range of different tbpB isotype I meningococcal strains
| Antigen | Animal no. | Cross-bactericidal titer on meningococcal tbpB isotype I straina:
|
||||
|---|---|---|---|---|---|---|
| B16B6 | 2713 | 64/92 | 106/NK | 2717 | ||
| Wild-type MBP-TbpB | 1 | 1,024 | 2,048 | ≥4,096 | 128 | 8 |
| 2 | 1,024 | ≥4,096 | >4,096 | 128 | <8 | |
| Mutated MBP-TbpB R243N | 3 | 4,096 | ≥4,096 | >4,096 | 256 | 64 |
| 4 | 4,096 | ≥4,096 | >4,096 | 512 | <8 | |
| MBP alone (control) | 5 | [4] | <8 | <8 | <8 | <8 |
a
Bactericidal titers were determined on N. meningitidis tbpB isotype I strains B16B6, 2713, 64/92, 106/NK, and 2717 grown under iron-limiting conditions. The bactericidal titer is expressed as the reciprocal of the last IgG dilution in the presence of which at least 50% of the initial bacterial load was killed. In most cases, IgG preparations from two individual rabbit sera were tested and titration was performed twice. The number in brackets indicates incomplete killing.