introduction to immunology - week 1

Question 1

what is the main function of the immune system

Answer 1

the immune system has to defend against a wide range of hostile pathogens

Question 2

what were the early vaccination strategies

Answer 2

• Edward Jenner in 1798, noted milkmaids who contracted and recovered from cowpox were immune to severe smallpox
  He inoculated fluid from cowpox pustules to offer protection against smallpox.
  Edward Jenner used pus (which he took from a dairy maid that contracted cowpox from a cow) as a vaccine for an 8-year-old James Phipps in 1798.

-Louis Pasteur observed that weakened pathogenic strains could provide protection against aggressive disease.
in 1891, Pasteur administered his first vaccination on a young boy named Joseph who got multiple rabid dog bites and the boy lived.

Question 3

what is Elie Metchnikoff’s do

Answer 3

Metchnikoff observed, described and named the process of phagocytosis, which is ingesting foreign matter by white blood cells.

Question 4

what is Paul Ehrlich’s side-chain theory

Answer 4

a variety of receptors (side-chain receptors) are expressed in blood cells which could bind to pathogens and inactivate them.
interaction between receptor and pathogen induces the cell to produce and release more of these receptors.
Ehrlich invented the term antigen.
an immune response is provoked if any substance is recognised as foreign by the immune system.

Question 5

what is the definition of immunogenicity and reactivity

Answer 5

immunogenicity - the ability to provoke an immune response
reactivity - the ability to react with antibodies or T cells

Question 6

what is the Host-Pathogen interaction

Answer 6

its a fine balance between the fighting force of immune system and virulence of a disease

Question 7

what affects the outcome of the pathogen and host interaction

Answer 7

what affects the pathogen is:
- mechanisms of pathogenicity
- immune escape mechanisms
- number of pathogens

what affects the host:
- genes regulating immune response
- health of host

Question 8

what are the primary organs

Answer 8

the primary organs are where immune cells are formed or matured, these include:
- bone marrow
- thymus

Question 9

what are the secondary organs

Answer 9

the secondary organs are where immune cells work
for example, the spleen where blood-borne diseases occur

Question 10

where do the cells of the immune system develop

Answer 10

the cells of the immune system develop from a stem cell in the bone marrow

Question 11

what cells are in natural immunity and specific immunity

Answer 11

the cells in natural immunity are:
- Granulocytes, which include:
> neutrophils
> eosinophils
> basophils
- monocytes
- natural killer cells

the cells in specific immunity lymphocytes are:
- T lymphocytes
- B lymphocytes

Question 12

what are neutrophils

Answer 12

they are
inflammatory cells,
first on the scene
phagocytes

Question 13

what are monocytes/ macrophages

Answer 13

they are
wound-healing cells
opsonisation
antigen-presenting cells
phagocytosis

Question 14

what are eosinophils

Answer 14

they are increased in allergy response
they produce major basic proteins that are toxic to helminth

Question 15

what are basophils/ mast cells

Answer 15

they are increased in allergy response
inflammatory cells

Question 16

what activities do activated complement proteins engage in

Answer 16

-they engage in the inflammatory response
- they adhere to microbial surfaces to attract phagocytes
- they puncture holes in the cell membrane so water can flood in and bust the cell
- they help clear antibody-antigen complexes that could otherwise cause inflammatory damage to tissues.

Question 17

what are the 2 arms of adaptive immunity

Answer 17

• humoral which is involved in the production of antibodies by activated B cells
• cell mediators which involve activated T-cells

Question 18

what are the 2 types of T-cells

Answer 18

1 - cytotoxic T cells which kill infected host cells
2 - helper T cells with the production of cytokines promote:
> antibody production of B cells
> activate macrophages to kill intracellular pathogen like phagocytosis

Question 19

what is innate immunity

Answer 19

innate immunity is:
- epithelial barriers
- anti-microbial peptides
- phagocytes
- complement system
- acute phase reactants
- natural killer cells

Question 20

what is adaptive immunity

Answer 20

adaptive immunity relies on the function of T and B lymphocytes:
- B cells produce antibodies
- T cells can either kill (cytotoxic), help or suppress

Question 21

what do cytokines do

Answer 21

cytokines are immunological ‘hormones’ and they do the following:
- stimulate the immune system
-regulate immune system activities
-activate inflammatory cells
-stimulate the production of different blood types in bone marrow
-anti-viral activity
- inhibit certain cell types, e.g. tumours

Question 22

what are active and passive immunity

Answer 22

active immunity
immunity following the disease or vaccine

passive immunity
immunity donated from another individual, e.g. mother to fetus

Question 23

what is B-lymphocyte and T-lymphocyte receptor

Answer 23

B-lymphocyte
their antigen receptor is on the cell surface and is membrane-bound immunoglobulin.
plasma cell release immunoglobulin into the body fluids.

T-lymphocyte
the T-cell receptor recognises the antigen
The T-cell receptor is membrane-bound but is not secreted into body fluids.

Question 24

what are the 4 properties (4 R’s) of specific immunity

Answer 24

the 4 R’s of specific immunity are:
- recognition of the foreign antigen
- response, which is provoked by highly specific antigens, then mounted for elimination
-remembers
immunological memory is built through multiple exposures to the same antigen
-regulates
once the infection load is reduced, the immune response diminishes

Question 25

what happens in innate immunity (0-4h)

Answer 25

infection by pathogen –> action of innate effectors ( innate effectors are immune cells and soluble molecules involved in the immune response) –> removal of pathogen

Question 26

what happens in early induced response (4-96h)

Answer 26

infection by pathogen –> recruit innate effectors –> activation of innate effectors –> removal of pathogen