IIH L19-L21 The Immune System in Health Block

Question 1

What is passive vaccination? L19

Answer 1

Uses pre-formed elements of the immune system that are transferred to a person so they are immediately protected

Question 2

Physiological example of passive vaccination? L19

Answer 2

Transfer of maternal IgG into the foetal blood

Question 3

How long does maternal IgG provide protection for the newborn? L19

Answer 3

4-6 months

Question 4

Examples of passive vaccines? L19

Answer 4

Rhesus D
VZV
Tetanus (animal serum)

Question 5

What is active vaccination? L19

Answer 5

Occurs naturally when a person comes into contact with an infectious organism and immune memory is generated to prevent future infection with this organism

Question 6

Examples of active vaccines? L19

Answer 6

Whole, live-attenuated: BCG, MMR
Whole, dead: Rabies
Subunit, inactivated toxin: Tetanus
Subunit, recombinant protein: Hep B, HPV

Question 7

What are adjuvants? L19

Answer 7

Materials injected with the vaccine antigen to enhance the immune response

Question 8

Example of most-widely used adjuvant? L19

Answer 8

Alum

Question 9

What is complete Freund’s adjuvant? L19

Answer 9

Oil-in-water emulsion + dead mycobacterium

Question 10

What is the advantage of a complete Freund’s adjuvant? L19

Answer 10

Enhances expression of co-stimulatory molecules and cytokines by APCs increasing immune response

Question 11

Describe a thymus dependent antibody response. L19

Answer 11

An APC presents processed antigen to a T helper cell which promotes naive B cell class switching and somatic hypermutation to produce high affinity antibodies in germinal centres with long lasting memory B cells

Question 12

Describe a thymus independent type 1 antibody response. L19

Answer 12

Negative gram bacteria have LPS on their cell wall. LPS is made up of Lipid A, which is a target for the immune system as it not made by mammals. LPS responses are TI1 responses.

Question 13

Describe a thymus independent type 2 antibody response. L19

Answer 13

Bacteria that evade the immune system with a thick polysaccharide capsule have antigens that cannot evoke antibody responses until several months after birth, and full responsiveness isn’t until after 5 yo.

Question 14

What is a conjugate vaccine? L19

Answer 14

Created by attaching a polysaccharide organism to protein antigens

Question 15

How long does the adaptive immune system remain immature? L20

Answer 15

Throughout the first year of life

Question 16

When are lymphocyte numbers highest? L20

Answer 16

Just after birth

Question 17

Which class of antibody is prominent in the neonatal period? L20

Answer 17

IgM

Question 18

What are the symptoms of congenital Rubella? L20

Answer 18

Sensorineural deafness
Eye disease
Congenital heart disease

Question 19

Examples of congenital infection? L20

Answer 19

Toxoplasmosis
CMV
Herpes
Syphilis

Question 20

How long does maternal IgG protect the child? L20

Answer 20

First 3-6 months of life

Question 21

Which antibodies do not cross the placenta? L20

Answer 21

IgM and IgA

Question 22

Examples of IgG mediated autoimmune diseases? L20

Answer 22

Neonatal Myaesthenia Gravis

Neonatal heart block in RO positive SLE pts

Question 23

If there is a delay in the infant developing IgG, what is this called? L20

Answer 23

Transient Hypogammaglobulinaemia of Infancy (THI)

Question 24

What is immunesenescence? L21

Answer 24

Phenomenon that the immune system deteriorates with age

Question 25

What happens to NK cells with age? L21

Answer 25

INCREASE in number, decrease in cytotoxicity

Question 26

What happens to DCs with age? L21

Answer 26

Decreased ability to stimulate antigen-specific T cells

Question 27

What happens to monocytes/macrophages with age? L21

Answer 27

INCREASE in number, decrease in phagocytosis, decreased ROS

Question 28

What happens to neutrophils with age? L21

Answer 28

NO CHANGE in number, decreased chemotaxis, decreased phagocytosis, decreased ROS

Question 29

What happens to cytokines with age? L21

Answer 29

Increase in pro-inflammatory cytokines eg. IL-1b, IL-6, TNF and CRP Decrease in anti-inflammatory cytokine IL-10

Question 30

What happens to B cells with age? L21

Answer 30

DECREASE in naive B cells INCREASE in memory B cells Shortening of telomere length, reduced antibody affinity, increase in auto-antibodies

Question 31

What happens to T cells with age? L21

Answer 31

DECREASE in naive T cells INCREASE in CD4+ memory cells Shortening of telomere length, tendency to become auto-reactive

Question 32

Effect of age on vaccination response? L21

Answer 32

The reduction in naive T cells and decline in adaptive immunity means that for the annual flu vaccine that is encouraged for over 65s, less than 50% will produce a protective titre.

Question 33

What is the altered phenotype of T cells with age? L21

Answer 33

Loss of CD28 and gain of NKG2D