Immunology Flashcards
Describe the non specific defence mechanisms the body may launch against pathogen
- Pathogen engulfed by phagocyte
- Engulfed pathogen enters the cytoplasm of phagocyte into vesicle
- Lysosomes fuses vesicle release digestive enzyme
- Lysosomes enzyme break down pathogen
- Waste materials rejected from cell by exocytosis
Describe how a phagocyte destroys a pathogen in the blood
- Engulfes
- Forming vesicle
- Enzymes digest
Give two types of cell other than pathogen that stimulates an immune response
- Cancer cells
- Cells from other organisms
Describe how a vaccine leads to production of antibodies
- Contains antigen from pathogen
- Macrophage presents antigen on surface
- T helper cell with complementary receptor protein bind
- T cell stimulates B cell
- B cell divides to form clone secreting antibody ls
Explain humoral response leading to immunity
- B cells specific to antigen produced by mitosis
- B cells produce plasma and memory B cells
- Second infection produces antibodies quicker in larger quantities
Destine and explain the role of antibodies in stimulating phagocytosis
- Bind to antigen
- Cause agglutination
Active vs passive immunity
Involves memory cells vs doesnt
A = Production of antibody by plasma/memory cells
P = antibody introduction into body from outside source
Active takes time vs passive fast
Monoclonal antibody
Produced from the same B cell
Describe the structure of HIV
- Rna
- Reverse transcriptase
- Protein capsid
- Phospholipid envelope
- Attachment proteins
Describe how a person infected with HIV will develo AIDS
- High viral load leads to increased destruction of T helper cells
- Less activation of B cells
- Less production of plasma cells
- More able to destroy other microbes
Role of antibodies in a positive ELISA test
- Antibody binds to antigen
- Antibody with enzyme attached is added
- Antibody attaches to antigen
- Colour change
What is a antigen presenting cell
Cell that presents a non self antigen on their surface
What will the self shaping antigen look like on a cancer cell
Abnormal shape
Antigen
Foreign protein present on cell surface membrane
Stimulate a immune response
Phagocytosis
Phagocyte binds to pathogen via receptors
Pathogen engulfed by phagocyte by endocytosis
Lysosome fuses with pathogen
Lysozyme break down pathogen
Antigenic variability
Antigen mutation
Changes tertiary structure
So look different
Immune system cannot detect
Pathogen is not killed
B cells
Mature in bone marrow
Humoral response
T cells
Thymus gland
Cell mediated response
What do T cells respond to
Only respond to antigens which are presented on cell
Cell mediated response
- Pathogen engulfed destroyed by phagocytes become antigen presenting cell
- T helper cells have receptors on surface attach to antigen on APC
- Once attached- activates T helper cell divide by mitosis
- Cloned t helper cells differentiate- memory cells, cytotoxic T cells or phagocytes
Cytotoxic T cells
Destroy abnormal infected cells
Release perforin protein embeds in cell surface membrane making pore
Causes cell death
Where are cytotoxic T cells most common
Viral infection due to virus infect body cells
Sacrificed to prevent viral replication
Benefits of vaccination
- Prevent disease
- Eliminates disease eg smallpox
- Prevent epidemic
- Speed up body response to disease
Negitive - Allergic reactions
- Side effects
- Weakened virus becomes virulent
Antibody structure
Quaternary structure
Variable region top
Constant region doesn’t change
Long chain in middle = heavy chain
Short chain outside = light chain
Antigen antibodies complex
Antibodies bind to antigen
Agglutination
Antibodies flexible
Can bind to multiple antigen to clump them together
Easier for phagocytes to locate pathogen
Monoclonal antibody
Single type of antibody that can be isolated and cloned
What can monoclonal antibody be manipulated for
Medical treatment
Pregnancy test
Medical diagnosis
Passive immunity
Antibodies introduced into body
No pathogen therefore plasma and memory cells not made
No long term immunity
Active immunity
Immunity created by own immune system following exposure to pathogen or its antigen
Natural - following infection
Artificial - vaccine
Herd immunity
If enough of population vaccinated
Pathogen cannot spread easily amongst population
Protects those who aren’t vaccinated
Non specific response
Phagocyte moves towards pathogen via chemotaxis
Phagocyte engulf pathogen forms phagosome
Lysosomes fuses phagosome
Lysozymes digest pathogen
Pathogen is destroyed
Antigen presenting cells
Any cell presenting non self cell on cell membrane eg
Macrophages and cancer cells
