The AgI/II protein is expressed in the
serotype 2 and 9 wild-type strains but is absent in S2Δ
mutant strains. Western blot using cell wall extracts from S. suis serotype 2 (wells 1–3) and serotype 9 (wells 4–6): serotype 2 wild-type strain SC84 (well 1) and serotype 9 wild-type strain 1135776 (well 4); mutant strains S2ΔagI/II (well 2) and S9ΔagI/II (well 5); and complemented strains S2CΔagI/II (well 3) and S9CΔagI/II (well 6). Expected bands at approximately 180 kDa, shown by the black arrow, were observed for the serotype 2 and 9 wild-type and complemented strains, similar to that obtained with the purified AgI/II protein, rAgI/II (well 7), used as a positive control. MW: molecular weight marker.