FIG. 1.

(A) Schematic map of the plasmid pAdv142. The antigen expression cassette contains the hly promoter, followed by its signal sequence and 417 amino acids of the N terminus of nonhemolytic protein tLLO fused to human PSA. The PSA protein lacks its secretory signal sequence. (B) Expression and secretion of tLLO-PSA fusion protein by the strains dal dat 142 (lanes 2 and 4) and dal dat ΔactA 142 (lanes 1 and 3). The protein extracts were prepared by precipitating culture supernatants with 10% Trypticase soy agar. The Western blot represents the expression of tLLO-PSA in the total proteins secreted by the dal dat 142 and dal dat ΔactA 142 strains. The blot was stained with a 1:1,000 dilution of both anti-LLO and anti-PSA primary antibodies.