AI Article Synopsis
- EndoS is an enzyme from Streptococcus pyogenes that modifies antibodies to prevent immune response by hydrolyzing their glycan structure.
- Knocking out the EndoS gene in a specific GAS strain (M1T1) showed no real difference in how well the bacteria resisted immune cell killing or caused infections in mice.
- However, adding EndoS to other GAS strains (M49) made them more resistant to immune cells and more virulent in mice, suggesting that EndoS might enhance virulence in certain contexts.
Article Abstract
Background: The secreted enzyme EndoS, an endoglycosidase from Streptococcus pyogenes, hydrolyzes the N-linked glycan of the constant region of immunoglobulin G (IgG) heavy chain and renders the antibody unable to interact with Fc receptors and elicit effector functions. In this study we couple targeted allelic replacement mutagenesis and heterologous expression to elucidate the contribution of EndoS to group A Streptococcus (GAS) phagocyte resistance and pathogenicity in vitro and in vivo.
Results: Knocking out the EndoS gene in GAS M1T1 background revealed no significant differences in bacterial survival in immune cell killing assays or in a systemic mouse model of infection. However, exogenous addition and heterologous expression of EndoS was found to increase GAS resistance to killing by neutrophils and monocytes in vitro. Additionally, heterologous expression of EndoS in M49 GAS increased mouse virulence in vivo.
Conclusions: We conclude that in a highly virulent M1T1 background, EndoS has no significant impact on GAS phagocyte resistance and pathogenicity. However, local accumulation or high levels of expression of EndoS in certain GAS strains may contribute to virulence.
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|---|---|
| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3125321 | PMC |
| http://dx.doi.org/10.1186/1471-2180-11-120 | DOI Listing |
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