Characterization of Human Type C Enterotoxin Produced by Clinical S. epidermidis Isolates

Toxins

Lamine Baba-Moussa¹  Gilles Prévost²  Daniel Keller²  Philippe Riegel²  Chimène Nanoukon²  Rodrigue Tollo³  Dissou Affolabi³ 

[1] Faculté des Sciences et Techniques, Laboratoire de Biologie et de Typage Moléculaire en Microbiologie, Université d’Abomey, Calavi, Cotonou 05 BP 1604, Benin;Institut de Bactériologie, 3 rue Koeberlé, Université de Strasbourg, CHRU Strasbourg, Fédération de Médecine Translationnelle de Strasbourg, VBP EA 7290, F-67000 Strasbourg, France;Laboratoire de Microbiologie du Centre National Hospitalier et Universitaire Hubert Koutoukou-Maga, Cotonou 01 BP 386, Benin;

关键词: enterotoxins;    superantigens;    coagulase-negative staphylococci;    S. epidermidis;    mitogenicity;    cytokines;   

DOI  :  10.3390/toxins10040139

来源: DOAJ

【 摘 要 】

Staphylococcal Enterotoxins (SEs) are superantigens (SAg) originally produced by S. aureus, but their presence in coagulase negative staphylococci (CNS) has long been suspected. This study aims to better characterize a novel C-like enterotoxin expressed by clinical S. epidermidis strains, called SECepi. We isolated and characterized SECepi for its molecular and functional properties. The toxin was structurally modeled according to its significant similarity with S. aureus SEC3. Most of SEC amino acid residues important for the formation of the trimolecular Major Histocompatibility Complex II MHCII–SEC–T Cell Receptor TCR complex are conserved in SECepi. The functional properties of SECepi were estimated after cloning, expression in E. coli, and purification. The recombinant SECepi toxin exhibits biological characteristics of a SAg including stimulation of human T-cell mitogenicity, inducing and releasing high cytokines levels: IL-2, -4, -6, -8, -10, IFN-γ, TNF-α and GM-CSF at a dose as low as 3.7 pM. Compared to SECaureus, the production of pro-sepsis cytokine IL-6 is significantly higher with SECepi-activated lymphocytes. Furthermore, SECepi is stable to heat, pepsin or trypsin hydrolysis. The SECepi superantigen produced by CNS is functionally very close to that of S. aureus, possibly inducing a systemic inflammatory response at least comparable to that of SECaureus, and may account for S. epidermidis pathogenicity.

【 授权许可】

Unknown