Work

Native Properdin Binds toChlamydia pneumoniaeand Promotes Complement Activation

Year: 2010

Type: article

Abstract: Activation of complement represents one means of natural resistance to infection from a wide variety of potential pathogens. Recently, properdin, a positive regulator of the alternative pathway of complement, has been shown to bind to surfaces and promote complement activation. Here we studied whether properdin-mediated complement activation occurs on the surface of Chlamydia pneumoniae, an obligate intracellular Gram-negative bacterium that causes 10 to 20% of community-acquired pneumonia. We have determined for the first time that the physiological P₂, P₃, and P₄ forms of human properdin bind to the surface of Chlamydia pneumoniae directly. The binding of these physiological forms accelerates complement activation on the Chlamydia pneumoniae surface, as measured by C3b and C9 deposition. Finally, properdin-depleted serum could not control Chlamydia pneumoniae infection of HEp-2 cells compared with normal human serum. However, after addition of native properdin, the properdin-depleted serum recovered the ability to control the infection. Altogether, our data suggest that properdin is a pattern recognition molecule that plays a role in resistance to Chlamydia infection.

Source: Infection and Immunity

DOI: 10.1128/iai.00980-10

Authors: Claudio Cortes, V. P. Ferreira, Michael K. Pangburn

Institutions: The University of Texas Health Science Center at Tyler, University of Toledo

Language: English

Topic: Complement system in diseases

Subfield: Immunology

Field: Immunology and Microbiology

Domain: Life Sciences

SDG: Good health and well-being

Open Access status: green

Funders: American Heart Association, National Institutes of Health, National Heart, Lung, and Blood Institute, National Institute of Diabetes and Digestive and Kidney Diseases