The Staphylococcus aureus superantigen SElX is a bifunctional toxin that inhibits neutrophil function:SElX Inhibits Neutrophil Function

Bacterial superantigens (SAgs) cause Vβ-dependent T-cell proliferation leading to immune dysregulation associated with the pathogenesis of life-threatening infections such as toxic shock syndrome, and necrotizing pneumonia. Previously, we demonstrated that staphylococcal enterotoxin-like toxin X (SElX) from Staphylococcus aureus is a classical superantigen that exhibits T-cell activation in a Vβ-specific manner, and contributes to the pathogenesis of necrotizing pneumonia. Here, we discovered that SElX can also bind to neutrophils from human and other mammalian species and disrupt IgG-mediated phagocytosis. Site-directed mutagenesis of the conserved sialic acid-binding motif of SElX abolished neutrophil binding and phagocytic killing, and revealed multiple glycosylated neutrophil receptors for SElX binding. Furthermore, the neutrophil binding-deficient mutant of SElX retained its capacity for T-cell activation demonstrating that SElX exhibits mechanistically independent activities on distinct cell populations associated with acquired and innate immunity, respectively. Finally, we demonstrated that the neutrophil-binding activity rather than superantigenicity is responsible for the SElX-dependent virulence observed in a necrotizing pneumonia rabbit model of infection. Taken together, we report the first example of a SAg, that can manipulate both the innate and adaptive arms of the human immune system during S. aureus pathogenesis

Exploring host-pathogen interactions through genome wide protein microarray analysis

This study was sponsored by Novartis Vaccines, now part of the GSK group of companies, which was involved in all stages of the study conduct and analysis. L.Sc. and A.L. were the recipients of a Novartis fellowship from the Ph.D. program in Cellular and Molecular Biology of the University of Bologna. B.B. is the recipient of a Novartis fellowship from the Ph.D. program in Biochemistry and Molecular Biology of the University of Siena. A.F.H. was the recipient of a Marie Skłodowska-Curie Intra-European Fellowship (PIEF-GA-2012-328377). We thank Dr. Stefano Bernuzzi from Immunohematology and Transfusion Medicine Department, San Matteo Hospital, Pavia, for providing human blood samples for WHB experiments. We thank Giorgio Corsi for artwork

Genetic testing and common disorders in a public health framework: how to assess relevance and possibilities

This paper discusses genetic testing and common disorders from a health-care perspective. New possibilities for genetic testing confront health-care workers with the question of whom to test and which test to use. This document focuses on genetic testing and screening in common disorders. The term ¿common disorder¿ is used for disorders that individually have a high impact on public health.Examples of common disorders include cardiovascular disease (CVD), stroke, diabetes, cancer, dementia, and depression. For a health-care practitioner ¿ unlike a geneticist or an epidemiologist ¿ it may not be clear whether a common disorder is due to one gene with a high risk of serious disease, or due to a combination of several genes and several environmental factors. This document will not consider germline prenatal or preconceptional testing, nor testing of biomarkers for tumor recurrence, but it will discuss testing of mutations in tumor tissue, since this may reveal susceptibility to certain forms of therapy. Also, pharmacogenomic applications will not be discussed in depth, although some examples will be given of pharmacogenomic testing. The outlne is as following: First, the terrain of common complex disorders is introduced. Different assessment frames for genetic testing and screening are discussed. The section following that examines the aims and strategies for genetic testing and screening in common disorders and discusses some examples of current testing and screening in Europe. The section ¿The economic evaluation of genetic tests¿ discusses the cost¿benefit relation of different types of tests and screening strategies and how they could be used in the clinic in a cost-effective way. The subsequent section addresses the ethical, legal, and social issues of testing and screening in common disorders. The last section addresses regulatory and intellectual property issues in the EU as well as the United States.JRC.DDG.J.2-The economics of climate change, energy and transpor