TABLE 3.
Complement-mediated bactericidal activity of guinea pig antisera measured against strain MC58 and two mutant strains derived from MC58
| Antiserum or MAb | Bactericidal activity (titer or MAb concn [μg/ml])a
|
||
|---|---|---|---|
| Parent | ΔNspA | PorA-Negative | |
| Sequential immunization | 1:290 | 1:32 | 1:484 |
| Mixed immunization | <1:4 | <1:4 | <1:4 |
| E. coli vesicle immunization | <1:4 | <1:4 | <1:4 |
| Anti-PorA P1.7 MAb | 1:3,000 | 1:2,200 | <1:4 |
| Anti-NspA 14C7 MAb | 204 | >820 | 182 |
| Anticapsular group B MAb | 150 | 75 | 75 |
a
That is, the concentration of antibody or dilution of polyclonal antiserum required to give 50% killing after 60 min of incubation with human complement compared to that of controls in the absence of antibody or in the presence of antibody and heat-inactivated complement. Typically, the CFU/milliliter at 60 min is 150 to 200% the CFU/milliliter at time zero.