COD Immunology Flashcards
What are the 4 main immunological strategies to defend the body?
ANATOMICAL BARRIER - skin and mucosal lining
CHEMICAL BARRIER - anti-bacterial peptides, lysozymes
STRATEGIC OUT POSTS - mucosal associated lymphoid tissue (MALTs)
SENTINELS/ GUARDS - epithelial cells, macrophages, dendritic cells
Which immune system is the 1st line of defense and which is the 2nd line of defense?
Innate immune system
Adaptive immune system
Innate or adaptive immune system?
Humoral components
Cell-mediated components
Adaptive
Innate or adaptive immune system?
Anatomical barriers
Humoral components
Cell-mediated components
Innate
How are lymph nodes useful in immunology?
Checkpoints for meeting pathogens
Meeting point for innate immune cells and adaptive immune cells
What is Haematopoiesis?
Refers to the commitment and differentiation processes that lead to the formation of all blood cells from haematopoietic stem cells. In adults, haematopoiesis occurs mainly in the bone marrow (medullary)
What are some Haematopoietic growth factors?
Act on pluripotent stem cells = Stem cell factor (SCF)
Act on early multipotential cell = IL-3, IL-4
Act on committed progenitor cells = G-CSF, M-CSF
What are some humoral components?
FLUIDS PLASMA INTERSTITIAL FLUID LYMPH SECRETIONS
Name some defensive chemicals, peptides and enzymes
Microbicidal and microbiostatic chemicals: Digestive tract: stomach acid, digestive enzymes, bile salts
Antibacterial enzymes that attack bacterial cell walls
Tears, saliva, Paneth cells: lysozyme and secretory
Antimicrobial Peptides (AMP) Secreted by epithelial cells into mucosal fluids Secreted by phagocytes into tissues
Describe Defensins
Disrupt cell membranes of bacteria and fungi and viral membrane envelopes within minutes
Insertion of the hydrophobic region into the membrane bilayer, which forms a pore
α-defensins: neutrophils and Paneth cells
β-defensins: epithelial cells and keratinocytes
Describe Cathelicidins
Cathelicidins are host defense peptides with antimicrobial and immunomodulatory functions
Constitutively expression: neutrophils, macrophages induced expression:
keratinocytes, lung and intestinal epithelia
Active cathelicidins in neutrophils can remain in phagosome or released by exocytosis
Cationic amphipathic peptide that disrupts membranes and is toxic to a wide range of microorganisms
Complement fragments C3a and C5a act on endothelial receptors to produce Local inflammatory responses. Describe these responses
Increase vascular permeability
Increase fluid to the tissue
Adhesion molecules on vascular endothelial cells
Activate mast cells - release inflammatory molecules
Terminal complement proteins polymerase to form pores (MAC) in the membranes of pathogens. Give some examples of terminal complement proteins
C5b, C6-9
Describe MAC
Membrane attack complex
Forms a pore in the lipid bilayer membrane
Destroys membrane integrity
Destroys the proton gradient across the pathogen’s cell membrane
MAC has a hydrophobic external face & a hydrophilic internal channel
What is opsonisation?
The coating of the surface of a pathogen by antibody and/or complement proteins to aid in the process of phagocytosis and destruction of the pathogen