Micro Test 3 Epidemiology, Flu, and HIV (Part 3)
Describe HIV in its simplest form.
2 copies +ssRNA
10-50 copies of : reverse transcriptase, protease, integrase
HIV will infect what 4 types of cells?
T helper cells
Cells of the macrophage lineage (monocytes, macrophages, and microglia)
Smooth muscle cells
Dendritic cells (antigen presenting cells in skin, mucosa membranes, and lymph nodes)
While HIV does NOT infect B cells, the B cells still play a part in HIV. What do they do?
Deliver HIV to lymphoid tissues where T cells mature
An HIV envelope contains two proteins, what are they?
The protein gp41 promotes what?
Membrane fusion of envelope and cell membrane to allow cell entry
The protein gp120 binds to what receptor on the cell?
The protein gp120 can change its conformation during infection. Why is this a problem?
It makes the antibody recognition difficult
HIV attachment and entry occurs in three steps. What are they?
1. Gp120 binds to CD4 receptor on a T cell
2. Gp120-CD4 complex binds to another receptor and causes gp41 to be revealed
3. Envelope and cell membrane can then fuse and allow the capsid to enter.
When gp120-CD4 complex binds to another receptor and causes the gp41 to be revealed, what does it interact with in the T cells, macrophages, and smooth muscle cells?
T cells have CXCR4
Macrophages and Smooth muscles have CCR5
After the three step process of HIV attachment and entry occurs, the gp41 is left on the membrane. This makes it possible for what to happen?
It makes it possible for neighboring cells to fuse with that cell.
When neighboring cells fuse with the gp41 its called what?
The HIV's dsDNA will incorporate itself into what upon cell entry?
The host cell's DNA
Once the dsDNA enters the hosts genome its called what?
The enzyme responsible for integration is called what?
True or false:
Provirus can lay dormant for years or be activated immediately.
RNA transcribed from the provirus can be used to do what?
Translate viral proteins or to be packaged into new virions
How does HIV get the envelope from its host cell?
By budding out through the wall
An HIV virus is NOT mature or virulent until what happens?
protease cleaves proteins and activates the assembly of the capsid
When a person is infected with HIV, there is a burst of viral ________ and release of virus from infected cells.
Primary infection symptoms of HIV are similar to what other virus?
The immune system will produce antibodies. What will happen to the number of free virions?
they will dramatically decrease and no symptoms are seen at this stage
Within the cells, latent infection continues and the virus simply does what?
While latent infection happens, the virus replicates and is released only to do what?
Infect other cells
The infection of other cells during the latent infection of HIV occurs at such a fast rate the body cannot replenish the cells lost. Over 5-10 years the number of ________ cells declines.
What do the T helper cells do?
If the T helper cells are lost, what is the effect on the body?
The ability to produce antibodies is lost, making it easier for the host to get sick
HIV was first recognized in what group of people?
Through what bodily secretions can HIV be transmitted?
Through what kind of contact can HIV be transmitted?
IV drug use
blood transfusions (rare now days)
organ transplants (rare now days)
accidental needle sticks
sharing razors and toothbrushes
across the placenta
For an HIV patient to be diagnosed with AIDS the patient must have antibodies against HIV and one or more of what rare diseases?
Most patients, when diagnosed with AIDS, have what unexplained side effects?
low CD4 count
The treatment of HIV is accomplished by focusing on what?
Multiple areas of viral replication
What does HAART stand for?
Highly Active Antiretroviral Therapy
What is HAART?
a "cocktail" of nucleoside analogs, protease inhibitors, and reverse transcriptase inhibitors
Is HAART a cure?
No, just a treatment
To get an HIV vaccine that is effective, it must generate sufficient ________ to prevent sexual transmission and infection.
HIV can spread through _______ to evade the immune system.
What is a long term non-progressor?
A person who is chronically infected with HIV but has not developed AIDS
What three possible ways do long term non-progressors keep from developing AIDS?
Infected with defective virions
They lack effective co-receptors (CXCR4/CCR5)
Have an unusually well developed immune system
What is the possible HIV cure that is currently being studied?
Bone marrow transplants replacing the infected immune cells with donor cells that have non-functional CCR5 co-receptors