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Standard 10 e
. Students
know why an individual with a
compromised immune system (for
example, a person with AIDS) may be unable to
fight off and survive infections by microorganisms
that are usually benign.
What are Retroviruses
• Have RNA not DNA
• Infected cells , DNA copy of RNA to
insert into the Host Cell’s DNA
• Lays dormant for long time
• HIV is a retrovirus
• Harder to stop because can undergo
more mutations.
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Basic facts about HIV/AIDS
• HIV is the virus that causes AIDS
• HIV/AIDS is treatable, but not curable
• Approximately 30,000 people in LA are
living with HIV
• You can’t tell by looking if a person is
living with HIV, the only way to know is
by taking an HIV antibody test.
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HIV attacks the body’s immune system
• The immune system recognizes and
attacks pathogens and antigens
• HIV attacks and destroys T-cells
• HIV replicates itself and attacks more Tcells to weaken the immune system so
that it no longer functions
• Compromised immune system –
weakened
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The 4 Fluids
Blood
Semen
Breast Milk
Vaginal Fluids
These are the four fluids that transmit HIV. The key to
protecting yourself from infection is to avoid these four
bodily fluids.
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Transmitting HIV
• HIV is transmitted when one or more of the
four fluids is transferred from one person to
another. The most common ways HIV is
transmitted is by:
• Unprotected oral, anal, or vaginal sex
• Sharing needles
• Breastfeeding from infected mother to baby
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What is HIV and AIDS all about?
• Caused by HIV (Human
Immunodeficiency Virus)
• Compromises your immune system
• Kills white blood cells (Helpers T-Cells)
and can lead to AIDS (Acquired Immune
Deficiency Syndrome)
• HIV contains 2 copies of RNA that
penetrate a cell and hide for long time
periods. In the infected cell, RNA is used
to synthesize viral DNA.
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4
How do you ensure you will never catch HIV?
Abstaining from sex means not participating in sex at
all. Abstinence is the only way to ensure that you will
never contract HIV. Condoms reduce the risk for HIV,
but they do not eliminate the risks altogether.
How HIV causes AIDS
• HIV invades immune system cells
especially helper T cells.
• These helper T cells have a vital role in
the immune system.
• When a helper T cell is activated (by
having an antigen presented to it, it
begins to divide into memory T cells and
effector T cells.
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Memory T cells
• Memory T cells do not fight against
the virus.
• Instead they are long-lived and can
generate an immune response
quickly if the same foreign protein is
encountered again.
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Why is HIV hard to treat?
Viral disguise
• Virus mutates and changing the proteins
on its outer surface
• These new surface proteins are not
recognized by the immune system’s
memory cells.
• Mutant virus particles with new surface
proteins survive immune system attacks
and begin a new round of infection
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Why is HIV hard to treat?
Viral disguise
• Each round of infection reduces numbers of
helper T cells because they are infected and
destroyed.
• Each lineage of T cells has a limited ability to
replicate, after a finite number of rounds of
replication the body’s supply of helper T cells
becomes exhausted. The immune system
eventually is overwhelmed and collapses.
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White Board questions follow.
What is the difference between HIV and
AIDS?
A HIV is a virus that affects the immune system; AIDS
describes a deficient immune system.
B HIV is a virus that affects the immune system; AIDS
is a bacterium that affects the immune system.
C HIV is a virus that affects the immune system; AIDS
is a virus that affects the whole body.
D HIV is a disease that can be cured; AIDS is a
disease that has no known cure.
Tuberculosis, meningitis, and hepatitis C are all
diseases that are more common in people with
HIV or AIDS. This is most likely because healthy
people without HIV or AIDS __________.
A can better fight off disease causing
agents
B
are not able to contract these diseases
C
have a compromised immune system
D have been vaccinated against such
diseases
How does the HIV virus cripple the
immune system?
A.
B.
C.
D.
destroys T–cells
increases T–cells
destroys H–cells
increases B–cells
When macrophages and helper T cells start
producing particles of HIV, __________.
A
the person will be immune to AIDS
B
the virus is spreading
C
helper T cells are being destroyed
D
Both B and C
A person that cannot fight off and survive infections
by microorganisms that are usually harmless is said
to have which of the following?
A
a healthy immune system
B
an increase in the amount of antibodies in the body
C
an increase in the amount of macrophages in the
body
D
a compromised immune system
A person with an immune system compromised by a
virus is unable to fight off infections because
__________.
A
cells are not able to stop multiplying
B
cells stop producing antigens
C
killer T–cells destroy healthy body cells
D
helper T–cells are being destroyed by the virus
Which of the following systems does HIV destroy?
A
circulatory
B
skeletal
C
nervous
D
immune