Figure 6.

Characterization of vacA gene of strain KE21. This Figure displays aligned vacA sequences of H. pylori KE21, J99, 26695, SouthAfrica20, and K26A1. The sequences shown focus specifically on the four main regions of diversity in vacA sequences that have been recognized, namely the signal sequence region or s-region (A), the intermediate region or i-region (B), the deletion region or d-region (C), and the middle region or (m)-region (D) [37,38,39]. The vacA alleles characterized by deletions in s-, i-, and m-regions correspond to s1, i1, and m1, respectively; otherwise they are classified as to s2, i2, and m2. In contrast, the vacA allele with a large deletion in d-region corresponds to d2 type; otherwise it is classified as d1 type. Multiple combinations of s-, i-, d-, and m-region types may be observed [37,39]. Of note, the strain KE21 vacA is of s1i1d1m1 allele.