Immunity Flashcards
State 2 differences between a specific and a non-specific defence mechanism.
specific vs non-specific
1. specific pathogens vs all
2. slower vs rapid
Among other places, lysosomes are found in tears.
Suggest a reason why this is so.
- protective covering of eye - thin to allow light through
- vulnerable to infection
- tear ducts = potential entry points for pathogens
What are pathogens?
- disease causing microorganisms
- that trigger an immune response
/ - viruses
- bacteria
- fungi
- protozoa
What are antigens?
- generate immune response when detected by the body
- usually proteins
- on surface of cells
What do antigens allow the immune system to identify?
- pathogens
- abnormal cells (cancerous cells/ tumours)
- toxins (by bacteria)
- foreign **cells from other organisms of same species **(eg. organ transplant)
State 2 similarities between B cells and T cells.
- form of wbc
- produced from stem cells
State 2 differences between T cells and B cells.
- cell-mediated vs humoral immunity
- mature in thymus gland vs bone marrow
What is a macrophage?
- Phagocytic cell
- releases lytic enzymes
- break down pathogenic cells
What do neutrophils do?
- engulf
- digest pathogens
What do phagocytes do?
- engulf pathogens
- destroy them using lysosomes
- then become APCs
Function of APCs
- present pathogenic antigens on cell mem
- signal T-lymphocytes
What do T-helper cells do?
Stimulate:
1. cytotoxic T-cells–> divide & proliferate
2. B-cells–> divide
3. further phagocytosis
4. memory T-cells (immunological memory for future infection)
What do cytotoxic T-cells do?
- kill infected cells
- through release of an enzyme that kills the cell
What are vaccines?
- a way of introducing antigens of a
- dead/ weakened pathogen into the body
- to stimulate production of antibodies & memory cells
State the 4 ways pathogens are made harmless to be used in vaccines.
- killing 🔪but leaving antigens unaffected (eg. cholera)
- weakening (attenuation)🫥- heating🔥 but leaving antigens (eg. oral vaccine against polio)
- purified 😇antigens removed from pathogen (eg. hepatitis B)
- inactivated toxins (toxoids)🤐- harmless but still triggers immune response (eg. Tentanus)
Why do some vaccines contain multiple antigens?
- protects against diff. strains of pathogens (eg. flu)/ diff. diseases (eg. MMR)
Why don’t vaccinations fully eliminate diseases?
- x induce immunity in some ppl (immunodeficiency)
- infected before enough antibodies for protection (slow primary response)
- antigenic variability- mutations
- objections to vaccinations ∵ moral, religious, ethical
Compare active and passive immunity.
A vs P
- long term vs short term
- ✔️immune response (make antibodies) vs ❌
- ✔️memory cells vs ❌
What are natural and artificial active immunity?
- natural- after being infected
- artificial- vaccination
What is passive immunity?
- given antibodies
- made by diff. organism
Give an example of natural passive immunity.
baby gets antibodies through:
1. placenta- maternal antibodies to foetal blood
2. colostrum- first breast milk
❗protection- temporart (only a few months after birth)- broken down in spleen & liver, x memory cells
Cholera
1. what it is
2. why no effective vaccine
3. symptom
4. factors increasing spread
- intestinal disease
- intestinal = hard to reach by immune system
- chronic diarrhoea
- ↑ mutation rate- antigenic variability + mobile pop
Cholera
1. what it is
2. why no effective vaccine
3. symptom
4. factors increasing spread
- intestinal disease
- intestinal = hard to reach by immune system
- chronic diarrhoea
- ↑ mutation rate- antigenic variability + mobile pop
Tuberculosis
1. risk factor
2. factors increasing spread
- ↑ HIV spread ↑ susceptible
- overcrowding, poor living conditions in poverty/ war-affected countries + mobile pop + growing elderly pop ↓ effective immune system ↑ susceptibility
Why is HIV called a retrovirus?
- reverse transcriptase converts RNA into DNA
- reverse of action of transcriptase
Briefly HIV vs AIDS
- HIV = virus
- AIDS = condition caused by HIV infection
Tuberculosis- spread through air
Suggest why widespread use of condoms might help reduce the incidence of TB in a population.
- condoms- prevents HIV infection
- ↓ no. of ppl w/ impaired immune systems- likely to contract & spread TB
What are monoclonal antibodies?
- produced by plasma cells
- all clones of one B-cell
Why is detergent added to the mixture of B cells and tumour cells in developing hybridoma cells?
- affects lipid component in mem–> holes
- detergent washed out –> mem reform
- in combination w/ adj cells
Explain why tumour cells are used to fuse with B-cells.
- B cells- short-lived, x divide outside body
- tumour cells- long-lived, divide outside body
- ==> long-lived B cells grown outside of body
