Lecture 19: immunology I Flashcards by Nancy Hu

What does CD stand for in immunology?

cluster of differentiation- this relates to the genetic loci where some genes are found

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What are some critical immune organs in the body?

lymph nodes
tonsils
spleen

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What are the tonsils?

generally termed as lymphatics, these are the hubs where your immune cells go to communicate with other immune cells
An average body has ~500-600 lymph nodes strategically positioned throughout the body

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Why is the bone marrow important?

This is where you get stem cells which are important

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What are potential targets for immune suppression?

Tonsils
lymph nodes (neck, armpits, grown)

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What are the main types of white blood cells?

granulocytes, lymphocytes, monocytes, natural killer cells

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What are the physical barriers?

skin
mucosa
intestine
tissue barriers (blood brain barrier)

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What are examples of immune mediators?

cytokines
chemokines
growth/differentiation factors
recognition molecules
killing molecules
adhesion molecules
eicosanoids
endocrine molecules

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What are examples of cytokines?

interleukins
interferon
TNFa

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What are examples of chemokines?

IL-8
MCP-1
CLs
CXCLs

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What are growth/differentiation factors?

Granulocyte colony stimulating factor

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What are recognition molecules?

MHC Class I and II
MIRs
these are important in order for the immune system to distinguish self from non self between healthy and damaged

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What are adhesion molecules?

ICAM-1
integrins
CD2

important for leukocyte diapedesis

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What are eicosanoids?

prostaglandins, leukotrienes

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What are endocrine molecules?

steroids,
Corticol releasing hormone
catecholamines
histamine

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What are proliferal immune cells?

immune cells in the blood.

These are predominantly neutrophils, followed by B cells, T cells

What do T cells, monocytes and macrophages have in common?

they all have incredible heterogeneity and functionality which can potentially be separated into different subsets

What is the innate immune system?

the immune response which is the first line rapid response

this is primitive,

What does the innate immune system involve?

natural killer cells
mast cells
eosinophils
basophils
neutrophils 
monocytes
macrophages
dendritic cell

these are not antigen specific but are collectively the first line defence against bugs
has no capacity to generate a memory population

Where are the cells of the innate immune system strategically positioned?

in the key barrier type places e.g.
skin (langerhans cells)
blood brain barrier (microglia, astrocytes) as that is where infections will occur

What is innate immunity important for?

the elimination of pathogens that might cause infection
the removal of dead or dying cells
the recognition of abnormal cell types

What are neutrophils?

main abundant white blood cell comprising of ~70% of WBCs

normally found circulating blood
migrates to sites of inflammation rapidly
short half life (hours-days)
often primary responders

What are the main actions of neutrophils?

phagocytose microbes and debris
release cytokines which amplify inflammatory response
degranulation and release granules containing antimicrobial peptides, proteases

What are natural killer cells?

-involved in surveillance of blood and tissues for infected and tumourogenic cells

What is MHC class I important for?

recognising normal healthy self | if this is not recognised, chances are NK cells will kill the affected cell.

How do NK cells kill?

by forming immunological synpase and injecting this into the target of lytic enzymes e.g. granzymes

What are monocytes and macrophages?

- very multi facted cells produced in the bone marrow | - monocytes circulate in the blood and leave to reside in tissues to become macrophages

What are the roles of monocytes and macrophages?

- remove pathogens and foreign bodies through phagocytosis - some kill pathogens and cells by releasing H2O2 or NO - recruit innate and adaptive immune systems through release of inflammatory cytokines - some monocytes can differentiate into tissue APC which are involved in antigen presentation to the t cells

What is the adaptive immune system?

This primarily constitutes T and B lymphocytes which each have the capacity to generate a population of memory cells

How do vaccinations utilise the adaptive immune system?

- they mount an adaptive general immunity to the baccine - there is usually an immunogen that boosts the immune system - this immunogen is recognised by T or B cells - the B cells produce an antigen while T cells produce a molecule that is ready when it encounters the antigen again

Can an adaptive immune system function without an innate immune system?

Yes. Although both systems work hand in hand together you will often the innate immune system will delay and process antigens to the T and B cells for the adaptive immune system

What are exampels of immune system failure?

- allergic reactions - pain from tissue injury/inflammation - autoimmune diseases - tissue rejection - immunodeficiency - tumour evasion - other forms of immune compromise

What are examples of anti-inflammatory strategies?

steroids and NSAIDs

What are NSAIDs?

non steroidal anti-inflammatory drugs which inhibit COX enzymes. This prevents PG and LT synthesis. - original NSAIDs were non selective and targeted both COX I and COX II - newer generation are COX II selective aspirin - oldest ibuprofen, naproxen, non selective Diclofenac- weak preference for cox II

What are steroidal drugs?

these work by binding to the glucocorticoid receptor. When this receptor doesnt have a ligand/agonist bound, it is found cytoplasmically. binding transfers this receptor to the nucleus to influence transcription of inflammatory genes, NFkb This results in a shift in the pro inflammatory and anti inflammatory genes being developed

What is dysfunctional about an allergy?

- adaptive immune system - this is thought to be due to the type of immune response which is no longer exposed to the poor sanitation we used to have - mast cells release histamine to stimulate the H1 receptors resulting in increased wells, oedema, itching. - treat by blocking these H1 receptors with antihistamines