FIG. 6.

Protection against ETA-induced inhibition of protein synthesis by antisera raised to different synthetic peptides. Serum samples from different groups (Gr) of rabbits were diluted 1:10 in leucine-deficient EMEM supplemented with [³H]leucine. Two LD₅₀s of ETA (final concentration, 30 ng/ml) were added to the diluted serum, and the mixture was incubated for 1 h at 37°C, before being added to monolayers of 3T3 fibroblasts. After 4 h of incubation at 37°C in the presence of 5% CO₂, [³H]leucine incorporated into protein extracted from the cells was measured with a beta counter. Protection was expressed as the percentage of [³H]leucine incorporated in the absence of ETA. Serum samples from each rabbit were tested in triplicate, and the data were plotted as the mean ± standard error for each group. Asterisks indicate statistical significance compared to toxin mixed with preimmune serum (P < 0.05) by one-way analysis of variance.