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Neisseria Meningitidis NalP Cleaves Human Complement C3, Facilitating Degradation of C3b and Survival in Human Serum

Elena Del Tordello, Irene Vacca, Sanjay Ram, Rino Rappuoli, Davide Serruto

Proc Natl Acad Sci U S A. 2014 Jan 7;111(1):427-32.

PMID: 24367091

Abstract:

The complement system is a crucial component of the innate immune response against invading bacterial pathogens. The human pathogen Neisseria meningitidis (Nm) is known to possess several mechanisms to evade the complement system, including binding to complement inhibitors. In this study, we describe an additional mechanism used by Nm to evade the complement system and survive in human blood. Using an isogenic NalP deletion mutant and NalP complementing strains, we show that the autotransporter protease NalP cleaves C3, the central component of the complement cascade. The cleavage occurs 4 aa upstream from the natural C3 cleavage site and produces shorter C3a-like and longer C3b-like fragments. The C3b-like fragment is degraded in the presence of the complement regulators (factors H and I), and this degradation results in lower deposition of C3b on the bacterial surface. We conclude that NalP is an important factor to increase the survival of Nm in human serum.

Chemicals Related in the Paper:

Catalog Number Product Name Structure CAS Number Price
AP80295416 Complement C3 from human serum Complement C3 from human serum 80295-41-6 Price
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