Immunology - Guest lecture 9
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Immunology - Guest lecture 9

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Questions and Answers

What role do cell wall anchored (CWA) proteins play in Staphylococcus aureus infection?

  • They facilitate adhesion to host tissues. (correct)
  • They contribute to infection by promoting bacterial motility.
  • They enhance the pathogen's ability to evade the immune response.
  • They are responsible for the production of antimicrobial peptides.

    • Which of the following correctly describes Staphylococcus aureus?

  • It is a facultative pathogen and can cause a wide range of diseases. (correct)
  • It only poses a risk in immunocompromised individuals.
  • It does not have any known virulence factors.
  • It is exclusively a community-acquired pathogen.

    • Which aspect of the host immune response is affected by neuroendocrine nicotinic receptor activation?

  • Boosting antibody production.
  • Enhancement of phagocytosis by macrophages.
  • Increased production of immune cells.
  • Suppression of antimicrobial peptide production. (correct)

    • What is a common strategy Staphylococcus aureus employs to avoid host defenses?

    <p>Mimicking host antigens.</p> Signup and view all the answers

    What distinguishes Staphylococcus aureus from other bacteria in terms of infection capability?

    <p>It can act as a pathobiont.</p> Signup and view all the answers

    What is the potential death toll due to antibiotic-resistant organisms by 2050?

    <p>10 million</p> Signup and view all the answers

    What is the annual cost of surgical site infections in the US?

    <p>$3.3 billion</p> Signup and view all the answers

    Which type of mast cells is exclusively associated with MRGPRX2 expression?

    <p>Connective tissue mast cells</p> Signup and view all the answers

    How quickly can mast cells be activated in response to stimuli?

    <p>Seconds to minutes</p> Signup and view all the answers

    What role do mast cells play in infection?

    <p>They play a crucial role.</p> Signup and view all the answers

    What is Catestatin known for in the context of skin injury?

    <p>It acts as a neuroendocrine antimicrobial peptide.</p> Signup and view all the answers

    What do MRGPRs, particularly MRGPRX2, mediate in bacterial infections?

    <p>Increased susceptibility to infections</p> Signup and view all the answers

    What characteristic distinguishes the impact of antibiotic resistance as highlighted in the content?

    <p>It presents a growing threat to public health.</p> Signup and view all the answers

    What is the primary hypothesis regarding MRGPRX2 and mast cells?

    <p>MRGPRX2-dependent activation of mast cells is crucial for healing infected wounds.</p> Signup and view all the answers

    What is the proposed effect of catestatin on bacterially infected wounds?

    <p>It improves healing by activating mast cells.</p> Signup and view all the answers

    Which cell type is involved in the study's investigation of catestatin's effects?

    <p>Mast cells</p> Signup and view all the answers

    What receptor is implicated in the activation of mast cells by catestatin?

    <p>MRGPRX2</p> Signup and view all the answers

    What specific outcome does catestatin achieve in mast cells, according to the study?

    <p>Induction of histamine release</p> Signup and view all the answers

    What measurement was analyzed in response to catestatin in the study’s workflow?

    <p>Prostaglandin D2 levels</p> Signup and view all the answers

    In what way did the study investigate the in vitro effects of catestatin on mast cells?

    <p>By measuring cytokine/chemokine gene expression.</p> Signup and view all the answers

    What aspect of the healing process is primarily addressed in the hypothesis related to catestatin?

    <p>Wound healing enhancement</p> Signup and view all the answers

    What is the primary function of mast cells in the context of pathogen recognition?

    <p>To detect pathogens and provide surveillance</p> Signup and view all the answers

    Which of the following tissues are mast cells known to localize in?

    <p>Respiratory tract and gastrointestinal tract</p> Signup and view all the answers

    What role does the receptor MRGPRX2/b2 play in mast cell activation?

    <p>It activates mast cells in a non-immunologic manner</p> Signup and view all the answers

    How does Staphylococcus aureus interact with mast cells in atopic dermatitis?

    <p>It produces δ-toxin that activates mast cells</p> Signup and view all the answers

    What type of ligands do MRGPRX2/b2 receptors specifically detect?

    <p>Cationic (positively charged) ligands</p> Signup and view all the answers

    In which species is the homolog of the human MRGPRX2 receptor found?

    <p>Mice with the receptor Mrgprb2</p> Signup and view all the answers

    What is the significance of mast cells having a spatial and temporal advantage over other leukocytes?

    <p>They quickly localize at sites of infection or inflammation</p> Signup and view all the answers

    What hypothesis is suggested regarding S.aureus and mast cells?

    <p>S.aureus activates mast cells to elicit a proinflammatory response</p> Signup and view all the answers

    What is catestatin's role in the context of wound healing?

    <p>It reduces bacterial load in infected wounds.</p> Signup and view all the answers

    Which receptor is crucial for mast cell activation in response to bacterial molecules?

    <p>MRGPRX2</p> Signup and view all the answers

    What therapeutic approach is suggested as a promising immunomodulatory therapy?

    <p>Enhancing the body's immune response with catestatin.</p> Signup and view all the answers

    What is a major concern regarding antimicrobial resistance (AMR)?

    <p>It has the potential to significantly worsen wound healing outcomes.</p> Signup and view all the answers

    What effect does catestatin have on mast cells?

    <p>It activates mast cells through MRGPRX2 receptor.</p> Signup and view all the answers

    Which of the following statements about enhancing the immune response is true?

    <p>It can utilize the body's own defense mechanism to combat infections.</p> Signup and view all the answers

    How does catestatin relate to bacterial infections?

    <p>It is a cutaneous antimicrobial induced after skin injury.</p> Signup and view all the answers

    What kind of response can MRGPRX2 and Mrgprb2 trigger?

    <p>An enhanced inflammatory response.</p> Signup and view all the answers

    Study Notes

    Mast Cells & MRGPRX2

    • Mast cells are found in barrier tissues and are the first line of defense against pathogens
    • They express MRGPRX2/b2 receptors which are activated by cationic ligands like those found on bacteria
    • This activation is independent of IgE and is part of the non-immunologic response
    • MRGPRX2/b2 activation leads to the release of inflammatory mediators which attract immune cells and can help kill bacteria

    MRGPRX2 & S.aureus

    • S.aureus can activate mast cells with δ-toxin
    • This activation leads to atopic dermatitis-like skin inflammation in mice

    MRGPRX2 & Wound Healing

    • MRGPRX2 activation can be crucial for wound healing
    • Catestatin can activate MRGPRX2 and has antibacterial and immunomodulatory properties
    • It has been shown that catestatin can reduce bacterial load in S.aureus infected wounds, but more research is needed

    S.aureus Pathogenesis

    • S.aureus is a facultative pathogen, meaning it can cause disease in certain conditions
    • It is a pathobiont, meaning it can be found in healthy individuals without causing disease
    • S.aureus can cause a wide range of diseases, from skin infections to pneumonia

    S.aureus Virulence Factors

    • S.aureus has surface proteins that allow it to adhere to hosts
    • Cell wall anchored (CWA) proteins are crucial for the adherence of S.aureus to the host, including the nasal vestibule
    • Spa is a CWA protein that can cause a variety of effects, including promoting bacterial survival and immune evasion

    Host Immune Response to S.aureus

    • The host has various defenses against S.aureus, including physical barriers, the innate immune system, and the adaptive immune system
    • Neutrophils are the first line of defense against S.aureus, but they can be overwhelmed
    • The adaptive immune system can respond to S.aureus, but the bacteria are capable of evading these responses

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    20241003Lecture9.pdf

    Description

    This quiz delves into the roles of mast cells and the MRGPRX2 receptor in immune responses, particularly in relation to S.aureus. It covers topics like activation pathways, inflammatory responses, and the implications for wound healing and skin inflammation. Test your understanding of these critical biological processes.

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