Analysis of δ expression across the serotypes. Western blot analysis was performed on lysates of strains representing all nine clinically relevant serotypes by using antiserum raised against recombinant δ. The serotype of the strain is indicated above each lane. Ia, A909; Ib, DK14; II, DK23; III, COH1; IV, CNCTC 1/82; V, CNCTC 10/84; VI, NT6; VII, 87-603; VIII, M9; (-δ), AJ200; rδ, recombinant delta protein.