Evasion of the Immune System by Pathogens lecture 15

Flashcards about how bacteria and viruses evade the immune system.

What virus causes genital sores?

Herpes simplex virus type two

What type of infection do herpes viruses typically cause?

Persistent infection

When envelope viruses are budding out, what do they take with them?

They take human membrane with them

What is one mechanism viruses use to avoid attack from the immune system?

Evasion of recognition

What do microbes do to evade the immune system after a disease establishes memory cells?

Change their antigen

What is the difference between antigenic drift and antigenic shift?

Antigenic drift is has only small variation, where Antigen shift has a large variation.

What causes antigen shift in viruses?

Reorganization of genetic material from two subtypes of the virus when in the same host.

The EBV virus produces a protein similar in function to which interleukin that inhibits immune response?

Interleukin 10

What does the CD59 molecule do to help viruses avoid the immune system?

Prevents the formation of the membrane attack complex

What happens to MHC class 1 molecules in viral-infected cells?

Downregulated

How does the adenovirus protein E1A interfere with antigen presentation?

It inhibits the transcription of MHC class 1 genes.

Besides interfering with antigen presentation, what final strategy do viruses use to evade the immune system?

They stop replicating.

Where does the herpes simplex virus go to hide when the immune system is strong enough?

Trigeminal ganglion

How does Treponema pallidum avoid recognition by the immune system?

It coats itself with fibronectin.

What do bacterial proteins A and G do to evade recognition?

They bind to the Fc fragment of the antibody.

What is the second strategy bacteria use to avoid immune attack?

Colonizing a safe location.

What do bacteria do to avoid immune attack, similar to viruses?

They change the antigen.

How many types of capsules does Streptococcus pneumoniae have?

More than 100

What is the important virulence factor that salmonella typhimurium use to avoid immune response?

Flagellum

How do mycobacterial tuberculosis evade phagocytosis or disruption?

Mycobacterial tuberculosis inhibits the fusion between phagosome and lysosome