Multivalency effects of hemagglutinin component of type B botulinum neurotoxin complex on epithelial barrier disruption

In this study, we investigated how the multivalency effect of HA influences its barrier‐disrupting activity. We prepared type B full‐length HA (three‐arm form) and mini‐HA, which is a deletion mutant lacking the trimer‐forming domain. Size‐exclusion chromatography analysis showed that mini‐HA exists as dimers (two‐arm form) and monomers (one‐arm form), which are then separated. We examined the multivalency effect of HA on the barrier‐disrupting activity, the E‐cadherin‐binding activity, and the attachment activity to the basolateral cell surface. Our results showed that HA initially attaches to the basal surface of Caco‐2 cells by carbohydrate binding and then moves to the lateral cell surface, where the HA acts to disrupt the epithelial barrier. Our results demonstrated that the multivalency effect of HA enhances the barrier‐disrupting activity in Caco‐2 cells. We found that the basal cell surface attachment and binding ability to immobilized E‐cadherin were enhanced by the multivalency effect of HA. These results suggest that at least these two factors induced by the multivalency effect of HA cause the enhancement of the barrier‐disrupting activity.

Source: Microbiology and Immunology - December 20, 2017 Category: Microbiology Authors: Sho Amatsu, Takuhiro Matsumura, Masahiro Yutani, Yukako Fujinaga Tags: Original Article Source Type: research