Intro Flashcards
What is immunity?
Immunity is the state of protection against foreign pathogens or antigens
Definition of immune system
The immune system is an integrated defense system composed of tissues cells and molecules. There are two types: innate and adaptive.
Describe the barriers to infection
- Skin/epithelial barriers prevent entry of pathogens
- Mucus prevents colonization
- Commensal microorganisms occupy niche
- Acid pH resists pathogens
- Enzymes attack pathogens
What are the immune system organs?
1st organs/primary lymphoid tissues:
- Bone marrow: immune cell production and B cell maturation
- Thymus: T cell maturation
2nd organs/secondary lymphoid tissues:
- MALT(mucosal associated lymphoid tissues[respiratory,gastrointestinal,genitourinary tract])
- Lymph nodes
- Spleen
What are the components of innate immunity?
Neutrophils, macrophages and monocytes. Dendritic cells, follicular dendritic cells. Eosinophil, basophil, mast cell, NK (natural killer) cells and other ILC (innate lymphoid cells)
What are the components of adaptive immunity?
B cells, T cells and circulating antibodies
Discuss resistance. Innate vs. Adaptive
Innate: resistance persists through generations, doesn’t change throughout lifetime
Adaptive: microbial resistance is not heritable
What are PAMPs, DAMPs and PRRs?
PAMPs: Pathogen Associated Molecular Patterns are genetic molecules found on microbes
DAMPs: Damage Associated Molecular Patterns
PRRs: Pattern Recognition Receptors recognize PAMPs and DAMPs and target them for clearance
What are the features of innate immunity?
Non specific, immediate and no memory response
What are the features of adaptive immunity?
Highly specific refined over time, develops over long period with initially slow response, memory response (immunological memory)
What events occur during innate response
- Recognition of a threat
- Activation of immune cells and complement system
- Production of cytokines, chemokines, acute phase proteins and defensins
- Upregulation of cell adhesion molecules
- Recruitment of cells to site
- Elimination of stimulus
- Resolution to response
- Tissue repair
Give example of PRR types that recognize PAMPs
Endosomal: TLR3, TLR7, TLR8, TLR9
Cytosolic: NOD-1, RIG-1, NLRP3
Cell surface: TLR2, TLR4, TLR5
Soluble: Mannose binding lectin, Ficolin
Give example of PRR types that recognize DAMPs
Cell surface: RAGE, TLR2, TLR4
Cytosolic inflammasome: NLRP3
What are the key features in pathogen recognition? (Innate immunity)
Toll Like Receptors (TLRs): Pattern Recognition Receptors (PRRs) that recognize Pathogen Associated Molecular Patterns (PAMPs) and lead to activation of NF-κB.
Examples of PAMPs are LPS(gram negative bacteria), flagellin(bacteria) and nucleic acid (viruses)
What are the key features in pathogen recognition? (Adaptive immunity)
Memory cells: activated B and T cells; subsequent exposure to previously encountered antigen —> stronger and quicker immune response
