Figure 3.

A909 and COH1 capsule switch strains produce similar amounts of capsule. A, pMBsacB mutagenesis was used for allelic exchange of cpsG and cpsH of the cps locus from a type III strain to a type Ia strain and vice versa. Capsule switch (CS) strains, A909 type III and COH1 type Ia, differ from the wild type (WT) in only these sections of the cps locus, but produce a different capsule type. Revertant strains (REV), A909 type Ia and COH1 type III, have undergone pMBsacB mutagenesis, but revert back to the native cpsG and cpsH, therefore producing their native capsule type. B, Latex agglutination with type Ia and type III antisera was used to confirm capsular switching in A909 and COH1 mutant strains. C and D, Enzyme-linked lectin assay using Maackia amurensis (MAL-I) lectin was used to estimate capsule amount in CS and REV A909 and COH1 strains. Data points represent technical replicates (n=8 for each strain) and median optical density (OD) was determined. The x-axis label indicates the expressed serotype (either Ia or III), the strain background (either A909 or COH1), and either CS or REV to indicate the specific strain type. Data shown are representative of multiple individual experiments (P=not significant [NS], Kruskal-Wallis test).