Regulation of immunity Flashcards
What is the main function of the immune regulatory system?
To maintain a balance between immune activation against pathogens and preventing damage to self-tissues
What are the components of the immune regulatory system?
Immune cells, complement system, cytokines, and other soluble factors in both innate and adaptive immunity
How is complement activity regulated to prevent tissue damage?
Complement regulatory proteins inactivate complement components that do not bind to pathogens to avoid host tissue damage
What is the role of complement regulatory proteins?
To limit complement activation on host cells and prevent excessive inflammation
What conditions are associated with complement regulatory system defects?
Uncontrolled complement activation leading to conditions like hemolytic uremic syndrome or age-related macular degeneration
What are natural killer NK cells?
Cytotoxic lymphocytes that target cells lacking MHC Class I molecules such as virus-infected and tumor cells
What regulates NK cell activity?
A balance of activatory and inhibitory receptors including KIRs and CD94-NKG2
How do macrophages contribute to immune regulation?
By producing anti-inflammatory cytokines like IL-10 and TGF-beta to maintain tolerance and limit inflammation
What are regulatory macrophages Mregs?
Macrophages that inhibit T cell proliferation and induce T regulatory cells via IL-10 and TGF-beta production
What is the significance of regulatory T cells Tregs in immune regulation?
Tregs suppress immune responses to maintain tolerance and prevent autoimmune diseases
How do dendritic cells regulate immune responses in the gut?
By sampling antigens and inducing Tregs in the absence of infection to maintain tolerance to food antigens and microbiota
What cytokines are critical for maintaining immune regulation?
IL-10 and TGF-beta
How does the gut immune system prevent responses to harmless antigens?
Through regulatory mechanisms involving Tregs macrophages and IgA-producing B cells
How do eosinophils assist IgA production in the gut?
They produce APRIL IL-6 and TGF-beta in response to commensal microbes to promote IgA class switching
What happens when immune regulation in the gut breaks down?
Dysregulation can lead to inflammatory diseases like Crohn’s disease or celiac disease
How does TGF-beta contribute to gut immune regulation?
It promotes Treg induction and class switching to IgA in B cells
What is the role of IL-10 in immune regulation?
IL-10 limits inflammation and helps maintain tolerance in mucosal tissues
What is physiological inflammation in the gut?
A state where Tregs dominate the immune environment preventing responses to harmless antigens while effector T cells remain ready to react to pathogens
What happens during a cytokine storm?
Excessive production of pro-inflammatory cytokines such as IL-1 IL-6 and TNF-alpha leads to tissue damage and systemic inflammation
How do macrophages in the gut maintain tolerance?
By being highly phagocytic producing IL-10 and avoiding significant inflammatory cytokine production
What are invariant NKT cells iNKT?
Innate-like lymphocytes with limited TCR diversity that recognize microbial glycolipids presented by CD1d molecules
What are mucosal-associated invariant T MAIT cells?
Innate-like T cells in the gut that respond to bacterially derived metabolites presented by MR1 molecules
What is the role of Tregs in preventing inflammatory bowel diseases IBD?
Tregs suppress effector T cells and promote tolerance to reduce inflammation in IBD
How does disruption of immune homeostasis lead to disease?
Uncontrolled immune responses can result in autoimmune diseases or chronic inflammation
What is the balance between effector and regulatory immunity?
Effector immunity fights infections while regulatory immunity prevents over-activation and self-tissue damage
How can regulatory mechanisms be harnessed in medical treatments?
By using therapies that enhance regulatory cell functions or cytokines like IL-10 and TGF-beta to treat autoimmune and inflammatory diseases
