Immune System - Immunity

Question 1

Primary immune response

Answer 1

Body encounter the foreign antigen for the first time
-a long latent period before antibodies are produced:
- antigen presenting cell phagocytosis to present antigen
- clonal selection: the right B or T cell needed to be found
- the right leukocyte need to differentiate

Question 2

Secondary immune response

Answer 2

Exposed to the same antigen again
-shorter latent time before antibodies produced:
- memory cell in circulation that immediately recognise the cell and clonal expansion (skip clonal selection)

Antibodies level is greater

May not feel symptoms at all

Question 3

Diagram of primary and secondary immune response

Answer 3

https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcTD6nL3wlRXRRSGEo4j1xAmUzZu-dgdKlQAJg&s

Question 4

What is immunity + how to get it
4 types of immunity

Answer 4

The host is no longer susceptible to the pathogen invasion
-gained via vaccination or natural

Natural immunity - immunity gained via natural exposure
Artificial immunity - gained from controlled way of delivering of antigen
Passive immunity - ready made antibodies transferred
Active immunity - make its own antibodies + memory cell

Question 5

Combination of active immunity

Answer 5

Natural active immunity: naturally exposed to antigen - causing primary exposure
-B and T cells created with antibodies. Memory cell created for secondary response = immune

Active artificial immunity: exposed to vaccine - cause primary response
-B and T cells created with antibodies. Memory cell created for secondary response = immune

Question 6

Combination of passive immunity

Answer 6

Natural passive: pass via placenta + breast milk
-treat diseases + symptoms
-but not produce antibodies + memory cell = not immune
-not permanent as body treat antibodies as foreign invader

Passive artificial: antibodies injected intravenously
-treat diseases that needs immediate treatment (rabies) or help immunocompromised
-allow for rapid treatment
-but not produce antibodies + memory cell = not immune
-not permanent as body treat antibodies as foreign invader

Question 7

Principle of vaccination

Answer 7

Promotes primary response without causing disease to create memory cells for secondary response if catch disease again - no symptoms

Difference between primary+ secondary immune response
-no latent period (produce antibodies immediately)
-faster than primary response
-higher level of antibodies produced

Question 8

Types of vaccination

Answer 8

Killed - pathogen that’s killed with chemical or heated

Attenuated - pathogens that are a-lived, but cultured under condition to be unpathogenic, or a similar micro-organism that is not pathogenic

Toxoid - inactive toxic compound from pathogen

Subunit - small fragments of pathogen or just their antigen

Question 9

Benefits of vaccine

Answer 9

-Provoke strong response to develop immunity
-no or few side effects
-long lasting immunity

Herd immunity
-idea if enough people are immune = reduced reservoir for pathogens
-protect those unvaccinated or immunocompromised

If pathogen mutate different antigen - take another one

Question 10

Ethical issues with vaccine

Answer 10

-Cost: can people afford it
-Effectiveness: does it work + justify the recourses to make + deliver it
-Rights of refusal
-Should it be compulsory
-Any side effects