Immune System 2 (chapters 7-8) Flashcards
Physical Barriers in Plants (1st LoD)
Bark
Waxy Intact Cuticle
Cellulose Cell wall
Thorns
Physical Barriers in Animals (1st LoD)
Intact Skin
Mucous Membrane
1st Line of Defence
Prevents entry of foreign mateial using physical and chemical barriers
Located on body’s surface
2nd Line of Defence
Non specific cellular and molecular responses to pathogens
Chemical Barriers in plants (1st LoD)
Peppermint oil - acts as antibacterial chemical
Citronella oil - Protects against fungi and bacteria
Mechanical Barriers (reflexes) (1st LoD)
Sneezing
Coughing
Vomiting
Diarrhoeia
Flushing Tears
Flushing Urine
Chemical Barriers in Humans (1st LoD)
Hydrochloric Acid in Stomach
Lysozyme in Tears
Microbiota barriers (1st LoD)
‘Microbes’ in the gut
exist in mutualistic relationship with person
prevent growth of colonies of other bacteria by outcompeting for nutrients, adhesion sights and secreting antimicrobial chemicals preventing growth of pathogenic bacteria
In return, the immune system tolerates their presence
Attenuated Vaccines
Whole Pathogen Vaccine
Contains whole bacteria or virus weakened through genetic modification or other means
- Can reproduce (unless virus)
Deactivated Vaccines
Whole Pathogen Vaccine
Contains whole bacteria or virus which has been killed so it CANNOT reproduce
mRNA Vaccines
Nucleic Acid Vaccine
Use RNA in a lipid membrane.
The RNA, once inside a cell, enters the ribosome, where it is ranslated to make the protein
Innate Immunity
Non Specific Immunity
1st and 2nd Line of Defence
Same for all infections
No ‘Memory’
Inflammation Symptoms
Physical condition
Reddened, swollen, hot painful reaction to injury/infection
Inflammation followed by discharge of pus
Inflammatory Response
- Blood vessels in the area around the damaged tissue dilate, causing an increase in blood supply to the area. (Vasodilation)
- The blood carries phagocytes to the area. Phagocytes also come from interstitial fluids surrounding the damaged tissue.
- Phagocytes release cytokines into the damaged tissues, which attracts more phagocytes to the area.
Macrophages
Engulf bacteria
Use cytokines to signal other Phagocytes to attack bacteria
Neutrophils
Respond to cytokines
Use phagocytosis to engulf bacteria
Main producer of pus
Mast Cells
Cause vasodilation - making cells bigger
Dendritic Cells
Produce antigen material and present it on cell surface to other cells in the immune system
Act as messengers between innate and adaptive immune systems
Initiate Immune Response
Eosiniphils
Granulocytes that are present in the respiratory, gastrointestinal and urinary tracts
Assist in defending against larger parasitic agents that are too large to be phagocytoses
Contain granules with toxic chemicals and histamine
Upon contact with pathogen, degranulation results in toxic chemicals being released.
Natural Killer Cells
Lymphocytes that kill virus infected body cells or tumour cells
Release toxic granules into abnormal cells to kill them
Cytotoxic (Cell Killing)
Complement Proteins
Made in liver, circulate bloodstream inactively
When activated:
- Attract Phagocytes
- Mark bacteria for destruction (Phagocytosis)
- Form cell destroying Membrane Attack Complex (MAC)
Interferons (INFs)
Signalling molecules released from virus infected host cells
- Cause nearby cells to heighten antivirus defence
- Cells stimulated by INFs prouce various enzymes to inhibit protein synthesis
Self Antigens
From within the body
Tolerated by the immune system
Non Self Antigens
From external environment
Identified as invaders and attacked by the immune system
Cellular Pathogen
microorganisms that are composed of cells
Bacteria
Fungi
Worms
Protozoa
Non Cellular Pathogen
microorganisms that are not composed of cells
Prions
Viruses
Allergens
A type of antigen that produces an abnormally vigorous immune response to a perceived threat that would otherwise be harmless to the body.
Role of Lymphatic System
The functions of this system include the absorption of excess interstitial fluid and its return to the blood stream,
absorption of fat from the small intestines
and the prevention of disease (main transport system for APCs and the main location of clonal selection.)
Role of Lymph Nodes
Substances that could be harmful to the body, such as bacteria or cancer cells, are trapped and removed by the lymph nodes.
Adaptive Immune Response to Intracellular Threat (Cell Mediated)
Antigen Presenting Cells concurrenlty initiate selection of T Helper and Naive T Cells
Naive T Cells stimulated by cytokines (from Th) and undergo clonal expansion and differentiation
Clones differentiate into either Cytotoxic T Cells or Memory T Cells
Upon contact with infected cell, T Cell binds to antigen MHC I complex
This induces secretion of cytotoxic chemicals to induce Apoptosis
Prolipherate
Makes a large amount
Adaptive Immune Response
Specific immunity
3rd Line of defence
Specific to particular infections
Long Term ‘Memory’
Herd Immunity
Resistance to the spread of an infectious disease within a population that is based on pre-existing immunity of a high proportion of individuals
ICONA
Imoblization
Complement Activation
Opsonization (MAC)
Neutralization
Agglutination
MHC I markers
MHC I markers are found on almost all body cells.
There role is to present a fragment of an antigen to alert the immune system if it becomes infected
Agglutination
Antibodies can bind together with antigens on 2 seperate pathogens
Makes it easier for Phagocytes to recognise pathogens and destroy them
Imobilization
Antibodies can restrict movement of Pathogens around the body through formation of large antigen antibody complexes
Artificial Immunity
Artificial is acquired from medical technology to purposely give immunity
Adaptive Immune Response to Extracellular Threat (Humoral)
1) Antigen Recognition
2) Antigen Presentation
3) Clonal Selection
4) Differentiation
5) Attack
MHC II markers
Role is to activate other parts of the immune system if an infection is detected anywhere on the body
Found only on:
- dendritic cells
- macrophages
- B cells
Natural Immunity
Results from unintentional exposure to antigen by interaction with other biological entities
Active Immunity
When a persons own immune system produces their antibodies
Passive Immunity
When someone has antibodies produced by someone else’s immune system
Role of B Lymphocytes
Lymphocytes that mature in Bone Marrow
Produce self antibodies
Once mature, move to circulatory and lymphatic systems
Part of Humoral Response
Fight infection outside of the cell
Role of Helper T Cells
They help activate B cells
Helper T cells recognise an antigen only when it is presented to them on MHC II markers
They can also help activate cytotoxic T cells to kill infected target cells.
Role of Cytotoxic T Cells
Acytotoxic T cellis aTlymphocyte that kills cancercells,cellsthat are infected (particularly with viruses), orcellsthat are damaged in other ways
Cytotoxic T cells only recognise antigens presented on MHC I markers
Role of T Lymphocyte
Lymphocytes that mature in Thymus gland
T-Lymphocytes circulate in the blood and are also found in the Spleen and Lymph Nodes
Fight infection within the cell as part of the Cell Mediated Response
Imobilization
Antibodies can restrict movement of Pathogens around the body through formation of large antigen antibody complexes
Complement Activation
Antibodies bind to cancer cell and interact with complement proteins
Compliment proteins can then go on to destroy cancerous cell either through MAC, or enhancing the function of other immune cells
Opsonization
Antibodies stick on the outside surface of pathogens and make it easier for cells of the immune system, such as phagocytes, to recognise them as foreign
Neutralization
Antibodies binding to pathogen to inhibit toxic effects
Agglutination
Antibodies can bind together with antigens on 2 seperate pathogens
Makes it easier for Phagocytes to recognise pathogens and destroy them
Lymphocytes
white blood cells that arise from Mitosis in stem cells in bone marrow
Cellular (2nd LoD)
Phagocytes:
- Neutrophils
- Macrophages
- Dendritic Cells
Natural Killer Cells
Mast Cells
Non Cellular (2nd LoD)
- Complement Proteins
- Cytokines
- Inflammation
- Fever
Membrane Attack Complex
a pore formed by complement proteins in the cell membrane of a pathogen, disrupting the membrane and leading to the pathogen’s destruction
B memory cells
provide the immune system with long-lasting memory.
3rd LoD
Cell Mediated Immunity
T Cells
Humoral Step 1. Antigen Recognition
Antigen Binds to B cells with complementary receptor
Humoral Step 2. Antigen Presentation
B Cell internalizes and displays processed epitope
Humoral Step 3. Clonal Selection
Interleukin stimulates B Cell to rapidly divide, forming a clone
Humoral Step 4. Differentiation
Some cells of the clone become Memory B cells
Most become Plasma cells
Humoral Step 5. Attack
Plasma cells synthesize and secrete antibody
Antibody employs means to render antigen harmless
Primary Lymphoid Tissue
Responsible for roduction and maturation of lymphocytes
Secondary Lymphoid Tissue
Responsible for maintanence of mature lymphocytes
