Senescent Erythrocytes Exhibit a Single-Hit Response to Staphylococcal Alpha Toxin

Kantor, Lana; Fackrell, Hugh B.

doi:10.1159/000021979

Cited by 3 publications

(1 citation statement)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The assay was adapted from [ 35 , 36 ]. In detail, a 2 ml sample of blood from rabbits was washed three times with 40 ml of 1X PBS (610 g, 10 min).…”

Section: Methodsmentioning

confidence: 99%

Genotypic and phenotypic analysis of clinical isolates of Staphylococcus aureus revealed production patterns and hemolytic potentials unlinked to gene profiles and source

et al. 2016

View full text Add to dashboard Cite

BackgroundNosocomial infections caused by the bacterial pathogen Staphylococcus aureus can lead to serious complications due to the varying presence of secreted toxins. Comparative studies of genomic information and production rates are needed to assess the pathogenic potential of isolated strains. Genotypic and phenotypic profiling of clinical and colonising isolates of S. aureus was used to characterise the release of exotoxins. Blood isolates were compared with colonisation strains to determine similarities and differences of single strains and clusters.ResultsFifty-one fresh isolates obtained from colonised individuals (n = 29) and S. aureus bacteremia (SAB) patients (n = 22) were investigated. The prevalence of genes encoding for three cytolysins (alpha/beta/gamma toxin) and twenty-four superantigens (SEA-SElX) was determined. Isolates exhibited eighteen distinct combinations of superantigens. Sequence analysis identified mutated open reading frames in hla in 13.7 % of all strains, in selw (92.2 %) and in selx (15.7 %). All corrupted genes were associated with specific clonal complexes. Functional assessment of alpha toxin activity by a rabbit erythrocyte lysis assay revealed that supernatants lacking alpha toxin still displayed hemolysis. This was due to the presence of gamma toxin, as proven by inhibition experiments using antisera raised against the respective recombinant proteins. Alpha toxin, SEC, and TSST1 production was quantified by enzyme-linked immunosorbent assays on supernatants of all hla, sec, and tst positive isolates. Blood isolates and colonising strains showed comparable amounts of secreted proteins within a wide range. Agr types I to IV were identified, but did not allow a prediction of high or low production rates. In contrast, alpha toxin production rates between distinct clonal complexes clearly differed. Spa typing was performed and revealed thirty-two unique spa gene patterns and eight small clusters comprising nineteen isolates. Recognised spa-typing clusters displayed highly similar production rates.ConclusionProduction rates of the three most prevalent exotoxins varied within both groups of blood isolates and colonising strains. By comparing genotypes and secretion, we found that identical complex gene patterns did not allow predictions of toxin production and function. However, identification of spa typing clusters was suitable to predict similar quantities of released exotoxins.Electronic supplementary materialThe online version of this article (doi:10.1186/s12866-016-0630-x) contains supplementary material, which is available to authorized users.

show abstract

“…The assay was adapted from [ 35 , 36 ]. In detail, a 2 ml sample of blood from rabbits was washed three times with 40 ml of 1X PBS (610 g, 10 min).…”

Section: Methodsmentioning

confidence: 99%

Genotypic and phenotypic analysis of clinical isolates of Staphylococcus aureus revealed production patterns and hemolytic potentials unlinked to gene profiles and source

et al. 2016

View full text Add to dashboard Cite

show abstract

Red Blood Cell Susceptibility to Pneumolysin

Bokori-Brown

Petrov

Khafaji

et al. 2016

Journal of Biological Chemistry

View full text Add to dashboard Cite

This study investigated the effect of the biochemical and biophysical properties of the plasma membrane as well as membrane morphology on the susceptibility of human red blood cells to the cholesterol-dependent cytolysin pneumolysin, a key virulence factor of Streptococcus pneumoniae, using single cell studies. We show a correlation between the physical properties of the membrane (bending rigidity and surface and dipole electrostatic potentials) and the susceptibility of red blood cells to pneumolysin-induced hemolysis. We demonstrate that biochemical modifications of the membrane induced by oxidative stress, lipid scrambling, and artificial cell aging modulate the cell response to the toxin. We provide evidence that the diversity of response to pneumolysin in diabetic red blood cells correlates with levels of glycated hemoglobin and that the mechanical properties of the red blood cell plasma membrane are altered in diabetes. Finally, we show that diabetic red blood cells are more resistant to pneumolysin and the related toxin perfringolysin O relative to healthy red blood cells. Taken together, these studies indicate that the diversity of cell response to pneumolysin within a population of human red blood cells is influenced by the biophysical and biochemical status of the plasma membrane and the chemical and/or oxidative stress pre-history of the cell.The interaction of toxins with their target cells is generally characterized by a dose-response curve that is sigmoidal in shape (1). This shape is taken to reflect the differing susceptibilities of individual cells within the population. The fact that red blood cells (RBCs), with their less developed glycocalyx compared with other cell types (2), exhibit such a response is evidence that the initial interaction between the toxin and the plasma membrane is subject to, and probably the main determinant of, such variability. Therefore, it is important to understand the biochemical and biophysical factors affecting toxin-membrane interactions and the resulting variability of susceptibility within the same cell population.Individual RBCs within a population differ significantly (3) with respect to their shape, volume, and surface area. Some of these changes are related to cell age, due to the variety of mechanical and chemical stresses that an RBC undergoes in its life span of ϳ120 days (4, 5), and others can be associated with diseases, such as diabetes and with acute conditions, such as sepsis, among many others (6), and thus are likely to be present in the membranes of many other cell types.Previous work on bulk cell preparations revealed that in addition to its normal discocytic shape, the RBC at rest can assume a variety of other distinct shapes, such as echinocytes and acanthocytes, characterized by exterior projections, and stomatocytes with cup-shaped invaginations (7). Many of these unusual shapes appear in normal blood at a frequency of about 1%. However, during blood bank storage and in many inflammatory, degenerative, and microvascular disorders, the frequ...

show abstract

Anti-Aging Medicine LiteratureWatch

Pawelec¹

1998

Journal of Anti-Aging Medicine

View full text Add to dashboard Cite

Senescent Erythrocytes Exhibit a Single-Hit Response to Staphylococcal Alpha Toxin

Cited by 3 publications

References 13 publications

Genotypic and phenotypic analysis of clinical isolates of Staphylococcus aureus revealed production patterns and hemolytic potentials unlinked to gene profiles and source

Genotypic and phenotypic analysis of clinical isolates of Staphylococcus aureus revealed production patterns and hemolytic potentials unlinked to gene profiles and source

Red Blood Cell Susceptibility to Pneumolysin

Anti-Aging Medicine LiteratureWatch

Contact Info

Product

Resources

About