19 research outputs found

    A Stylistic Study into the Poem “The Lost Alternative” By the Poet: Nizar Abu Naser

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    This study was performed based on the poem “the Lost Alternative” by the poet Nizar Abu Naser. This poem is part of the divan “the Lost Alternative.” To conduct the study, the stylistic method was adopted. Thus, the title, as well as the stylistic levels such as the language, combinations, visualization, and rhythm were studied. That is, the role of different styles in enriching the text and its semantic and aesthetic aspects were investigated

    Host and pathogen hyaluronan signal through human siglec-9 to suppress neutrophil activation

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    Abstract: Inhibitory CD33-related Siglec receptors regulate immune cell activation upon engaging ubiquitous sialic acids (Sias) on host cell surface glycans. Through molecular mimicry, Sia-expressing pathogen group B Streptococcus binds inhibitory human Siglec-9 (hSiglec-9) to blunt neutrophil activation and promote bacterial survival. We unexpectedly discovered that hSiglec-9 also specifically binds high molecular weight hyaluronan (HMW-HA), another ubiquitous host glycan, through a region of its terminal Ig-like V-set domain distinct from the Sia-binding site. HMW-HA recognition by hSiglec-9 limited neutrophil extracellular trap (NET) formation, oxidative burst, and apoptosis, defining HMW-HA as a regulator of neutrophil activation. However, the pathogen group A Streptococcus (GAS) expresses a HMW-HA capsule that engages hSiglec-9, blocking NET formation and oxidative burst, thereby promoting bacterial survival. Thus, a single inhibitory lectin receptor detects two distinct glycan “self-associated molecular patterns” to maintain neutrophil homeostasis, and two leading human bacterial pathogens have independently evolved molecular mimicry to exploit this immunoregulatory mechanism. Key message: HMW-HA is the first example of a non-sialic acid containing glycan to be recognized by CD33-related Siglecs.HMW-HA engagement of hSiglec-9 attenuates neutrophil activation.Group A Streptococcus exploits hSiglec-9 recognition via its polysaccharide HMW-HA capsule to subvert neutrophil killing

    Host and pathogen hyaluronan signal through human siglec-9 to suppress neutrophil activation.

    No full text
    Inhibitory CD33-related Siglec receptors regulate immune cell activation upon engaging ubiquitous sialic acids (Sias) on host cell surface glycans. Through molecular mimicry, Sia-expressing pathogen group B Streptococcus binds inhibitory human Siglec-9 (hSiglec-9) to blunt neutrophil activation and promote bacterial survival. We unexpectedly discovered that hSiglec-9 also specifically binds high molecular weight hyaluronan (HMW-HA), another ubiquitous host glycan, through a region of its terminal Ig-like V-set domain distinct from the Sia-binding site. HMW-HA recognition by hSiglec-9 limited neutrophil extracellular trap (NET) formation, oxidative burst, and apoptosis, defining HMW-HA as a regulator of neutrophil activation. However, the pathogen group A Streptococcus (GAS) expresses a HMW-HA capsule that engages hSiglec-9, blocking NET formation and oxidative burst, thereby promoting bacterial survival. Thus, a single inhibitory lectin receptor detects two distinct glycan "self-associated molecular patterns" to maintain neutrophil homeostasis, and two leading human bacterial pathogens have independently evolved molecular mimicry to exploit this immunoregulatory mechanism
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