Cytokines and Chemokines Flashcards
What are cytokines and their general role?
Cytokines are messenger molecules regulating immune and inflammatory systems. They are produced by leukocytes and other cells acting on target cells with specific receptors.
What is the function of chemokines?
Chemokines are specialized cytokines inducing chemotaxis of immune cells guiding them to sites of infection or inflammation by forming a concentration gradient.
What are some key properties of cytokines?
Cytokines are pleiotropic locally active and function in cascades. They act on multiple cell types have short half-lives and work via cell surface receptors.
What does it mean that cytokines are pleiotropic?
Cytokines can affect more than one cell type and perform multiple actions simultaneously resulting in diverse biological effects.
What is cytokine redundancy and its significance?
Cytokine redundancy means several cytokines have similar properties and target cells ensuring backup in case pathogens block one cytokine’s action.
How do cytokines function within the body?
Cytokines act locally and are mostly acute mediators. They work paracrinally often near their production site with effects ranging from cell activation to gene expression.
What is the primary role of IL-8 (CXCL8)?
IL-8 is a chemokine inducing chemotaxis in neutrophils recruiting them to tissues at sites of infection or inflammation.
How do cytokines exert their effects?
Cytokines act through cell surface receptors with extracellular cytokine-binding domains and intracellular signal transduction domains.
What are pro-inflammatory cytokines and their effects?
Pro-inflammatory cytokines like IL-1 TNF-α and IL-6 induce local inflammatory responses recruit immune cells and increase vascular permeability.
What are anti-inflammatory cytokines and their effects?
Anti-inflammatory cytokines like IL-10 prevent cytokine production by CD4+ cells and IL-1RA inhibits IL-1 activity balancing immune responses.
What are the specific functions of IL-1?
IL-1 has two forms IL-1α and IL-1β that induce IL-2 and IL-2R expression in T cells, increase B cell proliferation and enhance Ig synthesis. It also mediates local inflammation. High levels can lead to septic shock.
What therapeutic uses do cytokines have?
Cytokines like G-CSF are used to speed neutrophil recovery post-therapy, IL-10 for psoriasis, and IL-2 IL-12 and IFN-α in cancer immunotherapy.
What cytokine blockers are used therapeutically?
Anti-TNF-α anti-IL-6 and anti-IL-1 are used in rheumatoid arthritis. Anti-TNF-α is also used in Crohn’s disease asthma and psoriasis.
What are the primary receptors for TNF-α and their roles?
TNF-RI (p55) induces apoptosis while TNF-RII (p75) induces cell activation mediating the diverse effects of TNF-α.
What are the systemic risks of cytokine activity?
Systemic cytokine activity can lead to hazardous effects like septic shock and organ failure often seen with IL-1 and TNF-α.
What are the therapeutic applications of soluble cytokine receptors?
Soluble receptors like sIL-1RI and sTNFR regulate cytokine activity by binding circulating cytokines controlling their effects and enabling targeted signaling.
What are the types and roles of interferons?
Type I interferons (IFN-α and IFN-β) are produced by many cell types and have antiviral effects inhibiting viral replication and enhancing immune responses. Type II interferon (IFN-γ) is produced by T cells and NK cells upregulates MHC class I and II expression and activates macrophages and neutrophils.
What are the specific functions of IL-2?
IL-2 promotes T cell proliferation differentiation and survival. It is critical for activating NK cells and maintaining Treg cells ensuring balanced immune responses.
What are the roles of IL-4 and IL-5 in immunity?
IL-4 drives Th2 differentiation enhances IgE production and supports responses to parasites. IL-5 stimulates eosinophil production and activation essential for combating helminths.
What is the role of IL-6 in inflammation?
IL-6 acts as a pro-inflammatory cytokine inducing acute-phase protein production in the liver stimulating B cell differentiation and serving as a marker of systemic inflammation.
What are the specific functions of IL-10?
IL-10 is an anti-inflammatory cytokine that suppresses cytokine production by T cells and macrophages maintaining immune homeostasis and preventing overactive immune responses.
What is the function of IL-17 in immunity?
IL-17:
- produced by Th17 cells
- recruits neutrophils to sites of infection
- promotes inflammation especially during fungal and bacterial infections.
What are the roles of TNF-α and TNF-β?
TNF-α is a pro-inflammatory cytokine that increases vascular permeability recruits immune cells and induces fever. TNF-β also known as lymphotoxin mediates cell death and supports tissue repair.
What is the role of GM-CSF in immune responses?
GM-CSF stimulates the differentiation of granulocytes and macrophages enhancing their function and aiding in recovery from bone marrow suppression.
