15 - introduction to immunity Flashcards Preview

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Flashcards in 15 - introduction to immunity Deck (30)
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1
Q

what is immunity?

A

the ability of an organism to resist a particular infection or toxin by the action of specific antibodies or sensitised WBCs

2
Q

how do we gain immunity?

A

ACTIVE
• natural - natural infection
• artificial - immunisation

PASSIVE
• natural - placental transfer of maternal IgG
• artificial - human IgG

3
Q

what are the 2 types of immunity?

A

innate

adaptive/acquired

4
Q

what is innate immunity?

A
  • present from birth
  • simple recognition systems
  • limited capacity
  • there before infection starts
  • patrols for infection
  • rapid response - minutes
  • no immunological memory
5
Q

what is adaptive/acquired immunity?

A
  • not present from birth
  • learns from invading organisms
  • sophisticated - highly specific recognition
  • specific memory
  • slower response - days
6
Q

what is SCID?

A

severe compromised immunodeficiency

not born with innate immunity

7
Q

goal of the immune system

A
  • to clear potential pathogens in a controlled and efficient process
  • minimal side effects
  • no pathology in host
  • appropriate duration
  • return to homeostasis
  • future protection
  • no self attack
  • remove potential tumours
8
Q

factors affecting our immunity?

A
  • general health
  • infection
  • nutrition
  • adverse environmental conditions
  • state of microbiome
  • pregnancy
  • genetic disorders
9
Q

what is a vaccine?

A

a substance used to stimulate the production of antibodies and provide immunity against 1 or several diseases

prepared from the causative agent of a disease, its products, or a synthetic substitute, treated to act as an antigen without inducing the disease

exposure to the antigen causes an immune response which will protect you in the future

10
Q

what is herd immunity?

A

immunising the majority of the population

susceptible people are indirectly protected

11
Q

why is there no vaccine for malaria?

A
  • costs
  • logistics
  • time
  • complexity
12
Q

4 main groups of vaccines

A
  • live
  • inactivated
  • attenuated
  • subunit
13
Q

live vaccines

A

small amount of a live virus

eg. MMR

14
Q

inactivated vaccines

A

organisms are dead but whole organism injected

15
Q

attenuated vaccines

A

live organism but has its virulence removed

eg. smallpox

16
Q

subunit vaccines

A

little bits of the virus/bacteria used to cause an immune response

cheapest and most efficient way

eg. meningitis

17
Q

immunity can either by humoral or cellular, whats the difference?

A

humoral - in the blood (antibodies)

cellular - in the cells of the immune system

18
Q

what are antibodies?

A

produced by plasma cells which are mature B lymphocyte cells

19
Q

what is clonal selection?

A
  1. a single progenitor cell gives rise to a large number of lymphocytes, each with a different specificity
  2. removal of potentially self-reactive immature lymphocytes by clonal deletion
  3. pool of mature naive lymphocytes
  4. proliferation and differentiation of activated specific lymphocytes to form a clone of effector cells
20
Q

cells of the immune system

A

all start as pluripotent stem cells

common/myphoid differentiates into T cells, B cells, NK cells and ILC

  • B cells produce antibodies
  • T cells are antigen specific
  • NK cells and ILC are not specific and cannot recognise antigens - part of the innate response as they cannot adapt
21
Q

what do monocytes do?

A

monocytes circulate in the blood and differentiate into macrophages in the tissue

22
Q

what are primary lymphoid tissues?

A

central lymphoid organs
•bone marrow
• thymus

produce and mature lymphocytes

23
Q

bone marrow

A

a soft, spongey, highly cellular tissue that fills the internal cavity of bones

produces B cells and T cell precursors (virgin lymphocytes)

24
Q

thymus

A

a 2 lobed organ

produced T cells
only 2-4% mature and exit the thymus

25
Q

what are secondary lymphoid tissues?

A
peripheral lymphoid tissues 
•lymph nodes 
• spleen 
• tonsils 
• mucosal associated lymphoid tissues (MALTs)

lymphocytes recirculate and if they meet antigen, unto clonal expansion and differentiate in the tissues

circulate in fluids - blood and lymph

adaptive immune responses occur in the secondary lymphoid tissues

26
Q

where do B cells start to proliferate?

A

in the germinal centres of lymph nodes

27
Q

what is MALT?

A

mucosal associated lymphoid tissue

a diffuse system of non-encapsulated, submucosal lymphoid tissue in the intestinal and respiratory tracts

28
Q

respiratory MALTs

A
  • nasopharyngeal lymphatic tissues (tonsils and adenoids)

* bronchus associated lymphatic tissue

29
Q

intestinal MALTs

A
  • Peyer’s patches
  • appendix
  • isolated follicles in intestinal mucosae
30
Q

different effector mechanisms depend on:

A
  • type of pathogen
  • localisation
  • stage of infection
  • challenge