Acute rheumatic fever and rheumatic heart disease (ARF/RHD) have long been described as autoimmune sequelae of Streptococcus pyogenes or group A streptococcal (GAS) infection. Both antibody and T-cell responses against immunodominant GAS virulence factors, including M protein, cross-react with host tissue proteins, triggering an inflammatory response leading to permanent heart damage. However, in some ARF/RHD-endemic regions, throat carriage of GAS is low. Because Streptococcus dysgalactiae subspecies equisimilis organisms, also known as β-hemolytic group C streptococci and group G streptococci (GGS), also express M protein, we postulated that streptococci other than GAS may have the potential to initiate or exacerbate ARF/RHD. Using a model initially developed to investigate the uniquely human disease of ARF/RHD, we have discovered that GGS causes interleukin 17A/interferon γ-induced myocarditis and valvulitis, hallmarks of ARF/RHD. Remarkably the histological, immunological, and functional changes in the hearts of rats exposed to GGS are identical to those exposed to GAS. Furthermore, antibody cross-reactivity to cardiac myosin was comparable in both GGS- and GAS-exposed animals, providing additional evidence that GGS can induce and/or exacerbate ARF/RHD.
The rapid diagnosis of septicaemic melioidosis will have an impact on reduction of mortality. Currently, this relies almost exclusively upon culture of the causative agent Burkholderia pseudomallei from clinical samples. In acute sepsis, blood is the preferred specimen for culture and therefore should be the target for a rapid diagnostic tool. A lateral flow immunoassay (LFI) for the detection of B. pseudomallei antigen has been developed. This was compared with molecular detection using the targets T3SS1 and IpxO. Forty-five clinical samples of EDTA blood, which were culture-positive, were tested using both modalities. The LFI had a sensitivity of 40 %, whilst molecular detection had a sensitivity of 20 %. The poor performance of molecular detection has been described previously and is largely related to the use of wholeblood specimens collected into blood tubes containing EDTA. Whilst suboptimal, the LFI would be an adjunct in the rapid diagnosis of melioidosis.
Exploitation of the (strept)avidin-biotin interaction is extremely valuable in a variety of biotechnological applications. Biotin is often covalently linked to proteins or nucleic acids. Determination of the degree of biotinylation of such macromolecules is essential for downstream applications. There is currently a gap in simple yet efficient assays for rapidly quantitating protein biotinylation, as staple methods may produce unclear results or rely on immuno-or competitive assays. We present a simple and reliable electrophoretic method to determine the relative extent of biotinylation of macromolecules. The method relies on complex formation between a biotinylated macromolecule and a streptavidin probe resulting in an electrophoretic mobility shift of the complex detectable by SDS-PAGE. Finally, a green fluorescent protein labelled streptavidin probe was developed to eliminate the need for staining and reduce assay time.
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