TABLE 2.
Summary of anti-NspA MAb surface reactivity for genetically diverse N. meningitidis serogroup B strains
| Strain | Surface reactivity (flow) of anti-NspA MAbs and/or complement-mediated BCAa
|
|||||||
|---|---|---|---|---|---|---|---|---|
| AL4
|
AL5
|
AL11
|
AL12
|
|||||
| Flowb | BCA | Flow | BCA | Flow | BCA | Flow | BCA | |
| 8047 | + | >60 | − | 45 | − | 15 | ++ | 8 |
| CU385 | ++ | >120 | + | >120 | + | >120 | ++ | >120 |
| BZ198 | ++ | 26 | ++ | 5 | ++ | 4 | ++ | 5 |
| S3446 | ++ | >60 | ++ | >60 | ++ | 60 | ++ | 32 |
| 1000 | + | >120 | − | >120 | − | >120 | ++ | 110 |
| BZ232 | variable | >120 | − | >120 | − | >120 | variable | >120 |
| NG3/88 | ++ | >120 | + | >120 | ++ | >120 | ++ | >120 |
| NGP165 | − | >120 | − | >120 | − | >120 | − | >120 |
| MC58 | variable | >120 | variable | >120 | variable | >120 | variable | >120 |
| M986 | − | >120 | − | >120 | − | >120 | − | >120 |
| BZ198ΔNspA | − | >60 | − | >60 | − | >60 | − | >60 |
BCA, bactericidal activity (concentration of MAb that when incubated for 60 min with bacterial cells and 20% human complement yielded a 50% decrease in CFU per ml compared to that at time zero).
Surface binding was measured by flow cytometry. With one exception, all strains were tested at MAb concentrations of 10 and 60 μg/ml. The exception, strain BZ198, was tested at 6 and 60 μg/ml. Results were scored as follows: −, less than 50% of total fluorescent events have intensity above background when tested at 60 μg of MAb per ml; +, ≥50% of total fluorescent events have intensity above background at 60 μg/ml; ++, ≥50% of total fluorescent events have intensity above background at 6 or 10 μg/ml; variable, subcultures ranged from − to ++ (see text).