HylS, a fragment of truncated hyaluronidase of Streptococcus suis, contributes to immune evasion by interaction with host complement factor C3b

After entering the host, pathogens have to evade multiple attacks from the immune system for survival. As an ancient defense mechanism, the complement system is used as the first line to defense against pathogen infections. C3 and its fragments play essential roles in immune surveillance and clearance of pathogens, but microbes have evolved many strategies to escape it.

Pulldown assay was used to detected the interaction between HylS and C3b. Deposition of C3b and Membrane Attack Complex on S.suis was detected via the FACSCalibur flow cytometer. Serum killing assays were used to compare the SC-19, SC-19hylA and ΔhylS. Mice colonization experiments.