FIG. 4.

Protection of E. coli EH237 against complement lysis by CD59_E. Human erythrocyte protectin was incorporated into E. coli EH237 as for Fig. 2, whereafter the bacteria were incubated (30 min, 37°C) with indicated concentrations of NHS. The ability of bacterium-bound CD59_E to prevent complement-mediated bacteriolysis was studied by counting the CFU of serial 10-fold dilutions of the bacterial suspensions. The survival of serum-treated bacteria is expressed as percentage of surviving bacteria exposed to NHSi. After incorporation of CD59_E, the survival (at 1.7% of NHS) rose from 4 to 45%. Mean (±SD) values of duplicates are shown in this representative example of two similar experiments.