Lecture 9. Challenges Faced by the Immune System and Overview

Question 1

How many serotypes of Streptococcus pneumoniae are there?

Answer 1

More than 90

Question 2

What can Streptococcus pneumoniae cause?

Answer 2

Acute sinusitis, otitis media, meningitis, septic arthritis, endocarditis, peritonitis, pericarditis, cellulitis as well as pneumonia

Question 3

What bacteria competes with S. penumoniae?

Answer 3

Haemophilus influenzae, S. penumoniae attacks H. influenzae with hydrogen peroxide whilst H. influenzae signals to the immune system to attack the S. pneumoniae

Question 4

What does C. tetani produce?

Answer 4

A potent neurotoxin tetanospasmin. When released in a wound it is absorbed into the circulation and reaches the ends of motor neurons all over the body, interfering with neurotransmitter release, and causing tetanus

Question 5

What is the fatality rate of tetanus?

Answer 5

~40% cases

Question 6

What causes African trypanosomiasis?

Answer 6

A protozoan carried by Tsetse flies
They acquire a dense layer of glycoproteins that continually change, allowing the parasite to dodge an attack from the host’s immune system

Question 7

What does Pneumocystis carinii cause?

Answer 7

Pneumocystis pneumonia

Question 8

What does Ascaris cause?

Answer 8

Ascariasis

Question 9

What does Schistosoma cause?

Answer 9

Schistosomasis

Question 10

What does Trypanosoma brucei cause?

Answer 10

Sleeping sickness

Question 11

What does Mycobacterium leprae cause?

Answer 11

Leprosy

Question 12

What does Leishmania donovani cause?

Answer 12

Leishmaniasis

Question 13

What does Plasmoidum falciparum cause?

Answer 13

Malaria

Question 14

What does Variola cause?

Answer 14

Smallpox

Question 15

What does Influenza cause?

Answer 15

‘flu

Question 16

What does Varicella cause?

Answer 16

Chickenpox

Question 17

What is the mutation rate during copying in HIV?

Answer 17

~1 in 10,000 bases

Question 18

Why is the antigenic drift rate being so high in HIV a problem?

Answer 18

It outpaces development of an effective immune response in an infected matrix individual and confounds attempts to develop vaccines

Question 19

How does HIV rapidly evolve?

Answer 19

Though mutation

Question 20

How does ‘Flu rapidly evolve?

Answer 20

Through recombination

Question 21

What caused the 1918 Spanish ‘flu epidemic?

Answer 21

A bird virus crossed the species barrier

Question 22

Which age group were mostaffected by the Spanish flu?

Answer 22

Healthy young adults (20-40 year olds)

Question 23

How many people died of Spanish flu?

Answer 23

20-50 million people died (between 1.2% and 3% of the world population at the time)

Question 24

How many people died of Asian flu in 1957?

Answer 24

~2 million

Question 25

What was the death rate of the Hong Kong 'flu in 1968?

Answer 25

Low

Question 26

What is antigenic variation?

Answer 26

Pathogens altering their surface proteins to avoid host immune responses

Question 27

How do the lungs have an immune response?

Answer 27

A mucus layer containing pulmonary surfactants that reduce surface tension

Question 28

How does skin have an immune response?

Answer 28

Skin is dry and keratinised

Question 29

What is the blood brain barrier?

Answer 29

Separates circulating blood from the brain extracellular fluid It has tight junctions around brain capillaries and are formidable obstacles to macromolecules of the adaptive system

Question 30

What is the innate arm of the immune system?

Answer 30

First line of defence, rapid No memory, non-specific Encoded in the germ-line Found in fungi, plants, invertebrates and vertebrates

Question 31

What is the adaptive arm of the immune system?

Answer 31

Slow to adapt Highly specific, has memory Somatic gene recombination Confined to vertebrate systems

Question 32

What is cell-mediated immuntiy?

Answer 32

Defence provided by specialised cells in blood and tissues: lymphocytes (adaptive immunity), granulocytes (innate immunity)

Question 33

What is humoural immunity?

Answer 33

Soluble-phase defence provided by secreted proteins in body fluids: immunoglobulins (adaptive immunity), complement proteins (innate immunity)

Question 34

What does the humoral arm rely on?

Answer 34

Barriers and chemical warfare and makes calls for help

Question 35

What is the cell mediated arm comprised of?

Answer 35

A range of phagocytic cells and natural killer cells that destroy virus-infected cells: all these cells respond to calls for help from the innate humoural arm

Question 36

What is APC (antigen presenting cells)?

Answer 36

Instruct T cells which kill infected cells and regulate B cells. B cells make antibodies