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Tracking HIV Resistance: The
CCR5 Allele
PowerPoint 1
Do Now
1. Explain to the best of your understanding the
difference between HIV and AIDS
1. HIV interferes with the body’s ability to trigger a
proper immune response. Which immune cell or cells
would you expect HIV to target in order to accomplish
this. Explain your logic.
1. Many people are confused by the way HIV is
transferred between people. In one column, list two
ways that HIV CAN be transmitted. In the other
column, list two ways that, contrary to popular belief,
HIV CANNOT be transferred.
1. Explain to the best of your understanding the
difference between HIV and AIDS
HIVHuman Immunodeficiency
Virus
AIDSAcquired Immunodeficiency
Syndrome
HIV AIDS once the
immune system is too
overwhelmed by the virus
1. Explain to the best of your understanding the
difference between HIV and AIDS
HIV primarily attacks CD4 cells in the
human immune system
Healthy person:
• 600-1200 CD4 cells/mm3 of blood
HIV Infection:
• As viral load increases, CD4 cells are
destroyed
• AIDS officially diagnosed when CD4
cells reach below 200 CD4
cells/mm3
Without many healthy CD4 cells, other
antigens that the body could
typically fight off may enter and
take over, eventually causing death
2. Which immune cell or cells would you expect
HIV to target in order to accomplish this. Explain
your logic.
CD4 Cells (Helper T)• Immune cell that acts
like the captain of the
immune system
• Receives signal from
macrophages and
orders B Cells and CD8
cells to seek and
destroy
2. Which immune cell or cells would you expect
HIV to target in order to accomplish this. Explain
your logic.
Logical Reasoning:
• By targeting CD4 cells,
HIV disrupts
downstream immune
signaling
• Without CD4 cells, B
cells and CD8 cells
cannot target invading
pathogens
2. Which immune cell or cells would you expect
HIV to target in order to accomplish this. Explain
your logic.
HIV docks to the CCR5 receptor
protein on the CD4 cell membrane,
invades the CD4 cell and begins
damaging it
Damaged CD4 cells cannot signal for
an immune response. HIV begins to
multiply in the CD4 cell
Within 24 hours 10 million-10 billion
new viruses can be produced. The
viruses are released out of the cell
and back in to the blood stream to
spread to new CD4 cells
The infected CD4 cell will eventually
die
3. In one column, list two ways that HIV CAN be
transmitted. In the other column, list two ways
that, contrary to popular belief, HIV CANNOT be
transferred.
Directions: Turn to your partner and compare
your lists. Once you’ve finished, take out the
handout that you received when you walked in.
You will have 10 minutes to complete it on your
own before we share out.