Immune evasion mechanisms by Leptospiras spp.: interaction with C1 esterase inhibitor and C4b-binding protein.

Author(s)

Leandro Carvalho Dantas Breda

• Document type: Master's Dissertation
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto de Ciências Biomédicas (ICB/SDI)
• Defense date: 2014-04-10

Examining board members

Lourdes Isaac; Enéas de Carvalho; Nancy Starobinas

• Advisor: Lourdes Isaac

Abstract

Leptospirosis is a zoonosis caused by bacteria Leptospira. The Complement System plays a crucial role in the immune response against Leptospira. Non-pathogenic leptospira is eliminated by complement while pathogenic is able to avoid complement activation by the acquisition of host complement inhibitors Factor H and C4BP. We verified that SCR 7 and 8 of C4BP alpha chain are responsible to interaction with outer membrane proteins of L. interrogans LcpA and LigBC while SCR 4, 7 and 8 are responsible to interaction with LigAC and L. interrogans. We characterized this protein-protein interaction and verified that is ionic strength dependent and is inhibited by heparin. C1INH, another important regulator of classical and lectin pathways, interacts with the surface of leptospiras pathogenic, non-patogenic and attenuated and it is still able to regulates the classical pathway. We also performed a killing experiment and verified that C1INH is important to the survival of leptospiras attenuated, been the first complement system evasion mechanisms verified at this strain. (AU)

• FAPESP's process: 11/14347-7 - Mechanisms of complement evasion by Leptospira spp: Interaction of Leptospira with C1 inhibitor and C4b-binding protein
• Grantee: Leandro Carvalho Dantas Breda
• Support Opportunities: Scholarships in Brazil - Master