Immunology Flashcards
Define immunity
State of possessing sufficient biological defenses to provide protection from invading pathogens
What kind of diseases are caused by an overactive immune system?
Allergies and autoimmune diseases
What are the primary lymphoid tissues?
Bone marrow and thymus
What are the secondary lymphoid tissues?
Spleen, tonsils, lymph nodes
What is the structure and function of the spleen?
White pulp - Maturation of WBCs (B/T lymphocytes)
Red pulp - Breakdown of RBCs, rich in macrophages
Capsule
What are the GALTs?
Tonsils, adenoids, appendix, Peyer’s patches
What are the primary antigen presenting cells?
Dendritic cells
How does innate immunity function?
Recognition of pathogen-associated molecular patterns (PAMPs) which trigger macrophages to phagocytose the microbe
How does adaptive immunity function?
Antigens specific to the pathogen are identified and bound by B-lymphocytes which causes maturation and antibody production. Antibodies bind to the antigens and enable macrophages to identify foreign molecules and engulf them
How does the complement system function in innate immunity?
Opsonisation Lysis of pathogens Chemotaxis Inflammation Cell activation
How does the complement system function in adaptive immunity?
Augments the antibody response
Promotes T-cell response
Elimination of self-reactive B-cells
Enhancement of immunological memory
How does the complement system function in the disposal system?
Clearance of immune complexes and apoptotic cells
How does the complement system indicate infection?
Increased [C-proteins] in blood tests
Define Chemotaxis
Movement of an organism or cell towards a chemical stimulus
Define Extravasation and diapedesis
Extravasation - Forcing blood or lymph out of a vessel into surrounding tissue
Diapedesis - Neutrophils crossing between tissue and blood through the endothelium
What are the 3 branches of the complement system?
Classical pathway - Antibody binding
Lectin pathway - Mannose-binding lectin pathway
Alternative pathway - Pathogen surfaces
Which proteolytic enzymes are activated in the classical pathway?
C1, C2 and C4.
C4 causes the cleavage of C3
Which proteolytic enzymes are activated in the mannose-binding lectin pathway?
MLB, MASP, C2 and C4.
C4 causes the cleavage of C3
Which proteolytic enzymes are activated in the alternative pathway?
B and D.
D causes the cleavage of C3
What happens once C3 is cleaved?
Coating of microbes leading to phagocytosis
Recruitment of inflammatory cells
Activation of C5, C6, C7, C8 and C9 leading to cell lysis via formation of the membrane attack complex
What are the bodily physical defences of diseases?
Physical barriers - Skin, Mucous membranes, endothelial cells
Mechanical defences - Skin shedding, Mucouciliary escalator, Excretions, blinking
Microbiome
What are the bodily chemical defences?
Enzymes + chemicals in bodily fluids Antimicrobial peptides GI tract digestive enzymes Plasma protein mediators Cytokines Inflammation-eliciting mediators
What are the bodily cellular defences?
Granulocytes
Lymphocytes
What are the main macrophage receptors expressed on its cell surface?
Mannose receptor Lipopolysaccharide receptor CD11b/CD18 receptor Scavenger receptor Glucan receptor
