CMB1003/L21 Innate Human Response in Action Flashcards
How is cytokine secretion mediated?
Self-limited
Describe the action of cytokines. (3)
Pleiotropic
Redundant
Local or systemic
Often influence action or synthesis of other cytokines
How do cytokines initiate their actions?
Membrane receptor binding
How is the expression of cytokine receptors regulated?
External signals
Describe the cellular response to cytokines. (2)
Changes in gene expression
Expression of new functions
What are the 3 major functional categories of cytokines?
Mediators and regulators of innate immunity
Mediators and regulators of adaptive immunity
Stimulators of haematopoiesis
What are mediators and regulators of innate immunity produced by?
Mainly by macrophages in response to infectious agents
What are mediators and regulators of adaptive immunity produced by?
Mainly by T lymphocytes in response to specific recognition of foreign antigens
What are stimulators of haematopoiesis regulated by?
Bone marrow stromal cells, leukocytes and other cells
Stimulate growth and differentiation of immature leukocytes
Name 3 important cytokines.
IL2
IL1
TNFa
Interferons
What are the 2 distinct groups of chemotractive cytokines?
CXC
CC
Give another name for CXCL8.
IL-8
What is the role of CXCL8? (2)
Chemotactic factor
Recruits neutrophils, basophils and T cells to site of infection
What is the role of IL-1B? (4)
Activates vascular endothelium
Activates lymphocytes
Local tissue destruction
Increases access of effector cells
What is the role of TNF-a? (3)
Activates vascular endothelium
Increases vascular permeability leading to increased entry of IgG complement
Increased fluid drainage to lymph nodes
What is the role of IL-6? (2)
Lymphocyte activation
Increased antibody production
What is the role of IL-12? (2)
Activates NK cells
Induces differentiation of CD4 T cells into TH1 cells
Describe antimicrobial peptides. (4)
Innate, small peptides
Amphipathic -> destabilise lipid bilayer
Immunomodulatory effects on host cells
Produced by various cells
What is the goal of inflammation? (3)
Increased blood supply (vasodilation)
Increased vascular supply (leaky)
Increased expression of adhesion molecules
Give 3 triggers of inflammation.
Pathogens
Tissue damage
Disruption/inappropriate immune response
Describe the initiation of inflammation. (3)
Bacteria trigger macrophages to release cytokines and chemokines
Vasodilation and increased vascular permeability cause redness, heat and swelling
Inflammatory cells migrate into tissue, releasing inflammatory mediators that cause pain
Give 3 mediators of inflammation.
Complement products (C5a -> C3a)
Macrophage, T-cell-derived cytokines
Mast cells
Prostaglandins, leukotrienes, thromboxane, NO
Describe the local inflammation in response to Gram negative bacteria from cut to hand. (3)
PRR on macrophage stimulated
Release of TNFa but controlled
Positive outcome
Describe endotoxic shock. (4)
Excessive cytokine release in Gram-negative bacterial infection
Widespread effects of cytokines on vascular endothelium
Circulatory shock
Disseminated intravascular coagulation (DIC)
Describe how systemic inflammation (toxic shock) occurs using the example of Gram negative bacteria in blood. (3)
PRR on macrophage stimulated
Uncontrolled release of TNFa
Negative outcome
What is a cytokine storm?
Elevated levels of circulating cytokines and immune cell hyper-activation
Give 2 GI host-immune interactions.
Tight junctions
Paneth cells secrete AMPs
Complement
Saliva, pH, bile, peristalsis
Microbiome
Describe Crohn’s Disease. (4)
Inflammatory bowel disease
Autoimmune
Autoreactive T cells against intestinal floral agents
Fatigue, fever, abdominal pain, diarrheoa, weight loss, skin lesions
Which cells cause inflammation? (2)
Macrophages
TH1 cell infiltration
Which humoral components cause inflammation? (4)
Cytokines
Complement
Altered AMP levels
Antibodies
