Medical - Innate Flashcards
Innate
- Non-Specific
- First Line of Defence
- Rapid Response
- No Memory
- Present From Birth
Neutrophile
Rapid Response
Eosinophil
Kills Parasites
Basophil
Inflammation
Macrophage
Longer Lasting
Effective
Regular contact with potential pathogens which are destroyed within minutes or hours, only rarely causing disease.
Entry Barriers
- Commensal Microbiome
- Physical Barriers
- Chemical Barriers
Commensal Microbiome
Vagina
Physical Barrier
Skin
Chemical Barriers
- Stomach Acid
- Saliva
- Tear Drops
Humoral immune mechanisms
Immunity is mediated by macromolecules found in the extracellular fluid, circulating in plasma, mucosal secretions and cerebrospinal fluid.
Interferons
Signalling proteins induced in response to stimuli
Opsonins
Molecules that bind foreign substrates make them more susceptible to phagocytosis.
Acute Phase Proteins examples
- Coagulation proteins
- Protease Inhibitors
- C-reactive protein (CRP)
Acute Phase Proteins
- Plasma proteins produced in response to any injury, inflammation or infection.
- Macrophage activation by bacteria a cytokine releases a liver stimulation then acute phase protein production.
Complement
- Facilitates foreign cell lysis or phagocytosis
- Over 30 plasma proteins - produced by the liver
- Highly regulated and coordinated system. (primary defence system).
- Works in conjunction with antibodies. (adaptive Immunity).
Three Pathways (complement)
- Classical (antigen attached to microbe).
- Alternative (Microbial cell surface)
- Lectin (Recognise mannose on cell surface).
Classical Pathway Steps
- C1 is activated upon binding to the Ag-Ab complex.
- Activated C1 cleaves C2 (C2a) and C4 (C4b)
- C2a and C4b then bind to form C3 convertase (C4b2a)
- C3 is then cleaved into C3a and C3b
- C3b binds to C3 convertase and forms C5 convertase
- Sequential addition of C6,7,8,9 then forms MAC.
Innate Defense Functions
- Trigger Inflammation
- Attract phagocytosis
- Opsonize antigens
- Cause cell Lysis
- Activate naiive B-lymphocytes
- Remove immune complexes
Cell Components in the blood which mediate immunity
- Phagocytes
- Natural Killer Cells (NKC)
Phagocytic cells
- Monocytes
- Macrophages
Monocytes
Mononuclear phagocytic leukocytes, After circulating for ~8 hours, mature into macrophages when they reach tissue.
Macrophages
Larger than Mono, resides in specific tissues, highly phagocytic.
Macrophages Surface receptors
- Pattern recognition receptors (PRRs)
- Bind pathogen-associated molecular patterns (PAMPs)