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Flashcards in Immunity Deck (66):

What are the ten stages of the HIV life cyle?

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  1. Free virus
  2. Attachment & entry
  3. Penetration
  4. Reverse transcription
  5. Integration
  6. Transcription
  7. Assemby
  8. Budding
  9. Freedom
  10. Maturation


What is first step of the HIV cycle?

Free virus


What is the second phase of the HIV cycle?

Attachment and Entry

  • Virus binds to CD4 molecule (Helper T cell) on its surface


Another name for the Helper T cell?



What is the third phase in the HIV cycle?


  • Virus empties into contents into cell


What is the fourth phase in the HIV cycle?

Reverse Transcription

  • Converts RNA to DNA
  • The reverse transcriptase enzyme makes a "mirror image" of viral RNA strands to create double-stranded DNA


What is the fifth phase of the HIV cycle?


  • Viral DNA is inserted into the cell's own DNA by the integrase enzyme
  • The viruse and your cell are one


What is the sixth phase in the HIV cycle?


  • When the infected cell divides, the viral DNA is "read" and long chains of proteins are made
  • Protein synthesis into making new HIV virus


What is the seventh stage of the HIV cycle?


  • Immature virus pushes out of the cell
  • Takes some cell membrane with it
  • The protease enzyme starts processing the proteins in the newly forming virus 


What is the ninth stage of the HIV cycle?


  • Immature virus breaks free of the infected cells


What is the tenth phase in the HIV cycle?


  • The protease enzyme finished cutting HIV protein chains into individual proteins
  • These combine to form the viral core 
  • Makes a new working virus


What is an antigen?


  • Marker/ badge on the outside of a cell


How does the immune system recognize antigens?

Helper T Cells

  • Also known as CD4s 


What are the immuni-dominant antigents of influenza?

Ig H & Ig N

(ex: H1N1) 


On what part of the influenza virus are the antigens located? 

Antigens N and H are located on the surface of the viruse


What occurs during an "antigenic shift"? 

The antigens change (shift) to create a new strain


What is antigenic shift?

Antigenic shift is the process by which two or more different strains of a virus, or strains of two or more different viruses, combine to form a new subtype having a mixture of the surface antigens of the two or more original strains


What are the componets of the yearly influenza vaccine? 

Antigens H and N


What are the reasons that your friend who had the flu shot but got the flu anyway?

  1. It was a different strain of the flu that your friend wasn't immunized for
  2. Had the flu already (waited too long to get the flu shot)


What other organisms can be affected by influenza? 

  • Pigs
  • Humans
  • Birds


How does the influenza virus spread within the organims and determines productive replication of the virus? 

Via mutations and antigenic shifting of the influenza virus


What is an epidemic? 


a widespread occurrence of an infectious disease in a community at a particular time


What is a cytokine storm? 

Cytokine storm

The body overreacts to the virus and it causes it to destroy its down organs

Rambo overreaction 


How does the immune response to yearly flue differ from that of the avian flu?

Cytokine storm 


The H1N1 influenza has been the cause of four pandemics in recent history: 1918, 1957, 1968, and 2009. How is this possible to have multiple H1N1 pandemics in the same century?

  1. Antigenic shift of H1N1 virus
  2. Loss of memory T and B cells in the human body


What possible outcomes might happen if swine flu (H1N1) and avian flu (H5N1) reassorted? 

Super flu- a flu that we have not experienced yet


For a virus to infect, it must bind to the host cells at membrane receptors known as "sialic acid" receptors. These receptors differ in diferent organisms. Humans have sialic receptors know as "2,6-linked" while birds have "2,3-linked". Pigs have both receptors. Explain why Asian countries are considered the "hot zone" for new viruses to emerge. 

The "new" flu starts in Asia, due to people, birds, and pigs living in close proximity, causing an antigenic shift in the influenza virus. 


How does HIV locate the proper cells to infect? 

HIV located the Helper T cells via its antigens


How does antigens relate to proteins? 

Antigens are the markers outside of a cell

Antigens are composed of proteins

Proteins are made by genes from DNA


How does antigens relate to genes?

Antigens are the markers outside of a cell

Antigens are composed of proteins

Proteins are made by genes from DNA


What specific cell does HIV infect in the human body?

Helper T Cells (CD4)


What is the job of the helper T cells?

The Helper T cells are the generals of the immune system

Commands the immune system 


What happens to the infected cells when the new HIV particles bud out of the cell? 

The Helper T cells die off due to the baby HIV viruses taking parts of the helper T's membrane

Holes in the cell membrane = cell death 


How long does it take for HIV to go from integration until new particles bud out?

3-6 months


What is the difference between HIV and AIDS?

  • HIV+ means you have the virus 
    • "Cause"
  • AIDS means you have the symptoms of the HIV virus
    • "Affect"
  • HIV- means you don't have the HIV virus


Why doe victims of AIDS have a higher rate of fungal infections, yeast infections, and bacterial infections than the rest of the population? 

Due to AIDS victims being immuno-compromised 

  • The immune system cannot attack pathogens/non self cells because the Helper T cells are gone therefore no commands are given to the cytotoxic T cells and B cells
    • The immune system can't be turned on due to the Helper T cells not secreting interleukin 2


What diagnostic tests can be done to monitor HIV infection in the body? 

T cell count

  • CD4 count is lower in people with HIV
  • CD8 count is unaffected (killer/cytotoxic T cells) 


HIV cannot fix mutations (changes in its genetic material) when it reproduces. How does this affect the ability to make an HIV vaccine? Why? 

  • The HIV virus is not going for accuracy, its going for spead and volume
  • The HIV virus continually changes therefore it has different antigic shifts (different looks) 
    • The body cannot remember the HIV virus 
    • Therefore no HIV memory cells 



What are the defense?

Levels of Defense

  1. Barriers
  2. Innate Defenses 
  3. Adaptive immunity 


What are some examples of barriers?


  • Skin
  • Mucus
  • Cilia
  • Saliva
  • Tears
  • Stomach acid
  • Sweat


What is innate defense?

Innate Defense

  • Innate = non specific/non choosy immune system
    • Innmate immunity is immunity that you are born with 
      • Unlearned)
    • Non-specific immunity 


What is inflammation?

Inflammation = swelling, redness, pain, pus, hotness


What occurs during the swelling mechanism of the inflammation process?

Swelling Mechanism:

  • Increase in blood flow = increase in WBCs to injured area


What is the main purpose of the WBCs?

Main purpose of WBCs is to destroy pathogens 


How is inflammatin initiated?

Inflammation is due to an increase in histamine (vasodilation)

  • The increase in histamine:
    • Is released via the mast cell
    • Dilates the blood vessels (vasodilation)
    • Makes the blood vessels "leaky"
    • Allows fluid to leave the blood and go to the location of the infection 


What is a fever?

Fever = increase in body temperature


What is the purpose of a fever?

Purpose of a fever

  • Increases body temperature so:
    • Increases WBCs speed ("soldiers on speed")
    • Decreases bacteria's speed


What is adaptive immunity?

Adaptive immunity = learned immunity

  • Known as specific immunity
    • Attacks only one thing
  • Has memory 


What are the two pathways of adaptive immunity?

  1. B Cell Pathway
    1. Humoral pathway
  2. T Cell Pathway
    1. Cell mediated immunity 


What are MHC Proteins?

MHC Proteins = major histocompatibility complex proteins

  • Is a set of surface cell proteins essential for acquired immunit system to recognize foreign molecules from body cells 


What is the purpose/function of MHC proteins?

Function of MHC Proteins

  • Self recognition
  • Marker/badge/ antigen 


What is autoimmunity?


  • When the T cells attack the body's own "self" cells 


What cell makes antibodies?

B cells make antibodies


What do antibodies do to pathogens?

Antibodies stick to pathogen in order to slow them down so that the WBC can catch up with them and destroy them


Where is the IgA found?

IgA Found

  • Body secretions 
    • Plasma
    • Tears
    • Milk
    • Tears


What is the function of IgA?

Function of IgA

  • Bathes & protects mucosal surfaces from attachment of pathogens


Where are IgD found?

Location of IgD

  • Virtually always attached to B cells 


What is the function of IgD?

Function of IgD

  • Cell surface receptor of immunocompetent B cell
  • Grabs the invader
  • Activates the B cell 


Where is IgE found?

Location of IgE

  • Secreted by plasma cells in the skin, mucsae of gastrointestional and respiratory tracts, and tonsils


What is the function of IgE?

Function of IgE

  • Releases histamine
  • Mediates inflammation and certain allergic reactions


Where are IgG found?

Location of IgG

  • Most common circulating antibody
  • Most abundant in plasma


What is the function of IgG?

Function of IgG

  • Crosses placenta
  • Primary and secondary responses
  • Provides passive immunity to fetus 


What is the location of IgM?

Location of IgM

  • Attached to B cell
  • Free in plasma


What is the function of IgM?

Function of IgM

  • First responder antibody
  • Potent agglutinating agent 


"Give Me An Excellent Doughnut"

  • IgG
    • "Bloody baby" (placenta)
  • IgM
    • First released (first response)
  • IgA
    • "Flows away" (body secretions)
  • IgE
    • Allergy (histamine)
  • IgD
    • Is on the B's (on B-cells)