Fig. 2.

Bactericidal activity of calf serum and guinea pig complement on E. coli. Data were the mean of two assays ± standard deviation. An index of < 1 would indicate a bactericidal effect. There was significant difference between D2 and C2 growth indexes mean (p < 0.05). There was no significant difference between C2 and E2 growth indexes (p > 0.05). A2: Fetal calf serum, B2: Heated fetal calf serum, C2: Normal calf serum, D2: Guinea pig complement, and F2: PBS. Each well of a 96-well microplate contained 50 μL of fetal calf serum (Fetal Calf Ser), heated fetal calf serum (Heat.Fetal Calf Ser), fresh normal calf serum (NC.Ser) or heated calf serum or guinea pig complement or PBS. A 50 μL of a suspension of E. coli was added to each well and then incubated for 1 hr at 37 ˚C. Sample of 10 μL from undiluted, and dilutions of 10^-1 and 10^-2 were taken before (time zero) and after incubation and were plated out on SBA and then incubated overnight. The bactericidal index was defined as CFU mL^-1 after incubation for 1 hr divided by CFU mL^-1 at time zero