Lecture 9. Challenges Faced by the Immune System and Overview Flashcards
How many serotypes of Streptococcus pneumoniae are there?
More than 90
What can Streptococcus pneumoniae cause?
Acute sinusitis, otitis media, meningitis, septic arthritis, endocarditis, peritonitis, pericarditis, cellulitis as well as pneumonia
What bacteria competes with S. penumoniae?
Haemophilus influenzae, S. penumoniae attacks H. influenzae with hydrogen peroxide whilst H. influenzae signals to the immune system to attack the S. pneumoniae
What does C. tetani produce?
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
What is the fatality rate of tetanus?
~40% cases
What causes African trypanosomiasis?
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
What does Pneumocystis carinii cause?
Pneumocystis pneumonia
What does Ascaris cause?
Ascariasis
What does Schistosoma cause?
Schistosomasis
What does Trypanosoma brucei cause?
Sleeping sickness
What does Mycobacterium leprae cause?
Leprosy
What does Leishmania donovani cause?
Leishmaniasis
What does Plasmoidum falciparum cause?
Malaria
What does Variola cause?
Smallpox
What does Influenza cause?
‘flu
What does Varicella cause?
Chickenpox
What is the mutation rate during copying in HIV?
~1 in 10,000 bases
Why is the antigenic drift rate being so high in HIV a problem?
It outpaces development of an effective immune response in an infected matrix individual and confounds attempts to develop vaccines
How does HIV rapidly evolve?
Though mutation
How does ‘Flu rapidly evolve?
Through recombination
What caused the 1918 Spanish ‘flu epidemic?
A bird virus crossed the species barrier
Which age group were mostaffected by the Spanish flu?
Healthy young adults (20-40 year olds)
How many people died of Spanish flu?
20-50 million people died (between 1.2% and 3% of the world population at the time)
How many people died of Asian flu in 1957?
~2 million
What was the death rate of the Hong Kong ‘flu in 1968?
Low
What is antigenic variation?
Pathogens altering their surface proteins to avoid host immune responses
How do the lungs have an immune response?
A mucus layer containing pulmonary surfactants that reduce surface tension
How does skin have an immune response?
Skin is dry and keratinised
What is the blood brain barrier?
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
What is the innate arm of the immune system?
First line of defence, rapid
No memory, non-specific
Encoded in the germ-line
Found in fungi, plants, invertebrates and vertebrates
What is the adaptive arm of the immune system?
Slow to adapt
Highly specific, has memory
Somatic gene recombination
Confined to vertebrate systems
What is cell-mediated immuntiy?
Defence provided by specialised cells in blood and tissues: lymphocytes (adaptive immunity), granulocytes (innate immunity)
What is humoural immunity?
Soluble-phase defence provided by secreted proteins in body fluids: immunoglobulins (adaptive immunity),
complement proteins (innate immunity)
What does the humoral arm rely on?
Barriers and chemical warfare and makes calls for help
What is the cell mediated arm comprised of?
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
What is APC (antigen presenting cells)?
Instruct T cells which kill infected cells and regulate B cells. B cells make antibodies
