Innate Immunity

What are PAMPS and give examples

• Pathogen associated molecular patterns

• Reconginsed by PRRs

→Bacteria: peptidoglycan, flagellin

→Fungi: zymosan

→Viruses: double stranded RNA

Describe the process of phagocytosis of bacteria

What are the key indicators of why micrboes are killed in the phagolysosome

• low pH

• H2O2 production 

• anti-microbiral peptides

• NO production 

• proteases and lysozyme

What is a PRR drug 

• Imquidmod 

• PRR agonist against warts

State the components of the innate immune system

• Barriers

• Reconginition of conserved molecules expressed by microbes

• Pathways and cells primed to activate in lack of missing self

What are the 3 outcomes of PAMP recognition

• Direct cytoxicity

• Opsonisation and phagoyctosis

• Intracellular signalling and inflammation

What triggers opsonisation and phagocytosis of a cell 

• Coating the foreign body with host molecules that makes attractive to phagocytic cells of immune system e.g. C3b

• Phagocytosis is the uptake of ingestion of particulate material by cells, purpose to destroy material through exposure to harsh chemicals

Explain how PRR signalling can trigger intracellular and inflammtion

-Liver: acute phase proteins (raised CRP level = release of cytokines)

What are the 3 innate barriers and their key components to help protect

• Keratinised skin

• Ciliated epithelium in lung

• Stomach acid

→exterior surfaces can also secrete proteins that protect those surfaces from colonisation (lysosome which breaks down peptidoglycan and anti-microbial peptides which disrupts the bacteria membrane)

What are DAMPS

• Damage associated molecular patterns = trigger immune activation

• increase exposure of phosphatidylserine on surface promotes phagocytosis 

What is the complement system

• Name given to a series of plasma proteins (zymogens) which co-operate to facilitate direct killing, opsonisation and inflammation

• Can occur spontaneously but kept in check

• Also driven by PAMPs and Ab from the adaptive immune system

Give an example of a PAMP

• Mannose

List 2 complement defs 

• Hereditary angioedema (C1 inhibitor)

• Paroxysmal nocturnal haemoglobinuria (xs MAC pore formation)

What increase in the complement system indicates a bacterial infection

• An increase in C3

• also for fungal

Issues with C5 and MAC formation marks an increase vunerability to what

• Nesseria infection

• G-ve bacterial infection

What are NK cells and their importance 

• not part of adaptive only innate !

• Killing is direct contact with cell and realse of factors to trigger apoptosis

State the chemical barriers in the innate system

• Low pH in stomach and urogential tract

• Anti-microbial peptides on skin

• Enzymes in secretion e.g tears

How is skin a barrier in the 1st line of defence 

• Dense keratinsed epitherlial cells 

• Secrete cytokines and TNF to alert immune cells in site of injury 

Draw and descirbe the classical pathway

Draw and descirbe the terminal pathway

Draw and descirbe the alternate pathway

Describe the steps of the acute phase response

• Local infection e.g. IL-6 reach liver and induce response

• C-reactive protein is released and MBL = Complement system

What is the role of CRP

• Bind to bacterial phospholipids from liver

• Acting as opsonin to enhance phagocytosis