Summary
Fibrinogen is a key player in the blood coagulation system, and is upon activation
with thrombin converted into fibrin that subsequently forms a fibrin clot. In the
present study, we investigated the role of fibrinogen in the early innate immune response.
Here we show that the viability of fibrinogen-binding bacteria is affected in human
plasma activated with thrombin. Moreover, we found that the peptide fragment GHR28
released from the p-chain of fibrinogen has antimicrobial activity against bacteria
that bind fibrinogen to their surface, whereas non-binding strains are unaffected.
Notably, bacterial killing was detected in Group A Streptococcus bacteria entrapped in a fibrin clot, suggesting that fibrinogen and coagulation is
involved in the early innate immune system to quickly wall off and neutralise invading
pathogens.
Keywords
Innate immunity - coagulation - fibrinogen - infection