Download MALFUNCTIONS of the IMMUNE SYSTEM

MALFUNCTIONS of the
IMMUNE SYSTEM
This lesson meets the following DoE Specific Curriculum Outcomes for Biology 11: 116-7
MALFUNCTIONS of the IMMUNE SYSTEM
• Abnormal functioning of the immune
system can cause two types of
problems:
– Immunodeficiency diseases
– Inappropriate attacks of the
immune system against nonthreatening agents (harmless cells)
IMMUNODEFICIENCY
• Immunodeficiency diseases may be
caused by a foreign agent, such as the
HIV virus, which attacks T cells.
• It may also result from a hereditary
condition, such as severe combined
immunodeficiency (SCID) that results
in the inability to produce B cells and
T cells.
AUTOIMMUNE DISEASE
• T cells or antibodies mistakenly
identify your own body cells as foreign
and consequently attack them.
AUTOIMMUNE DISEASE
• Renegade lymphocytes treat the
body’s cells as aliens and make
antibodies to attach to their own cell
membranes.
• Drugs or serious infections can
weaken the suppressor T cells, leaving
the body vulnerable to autoimmune
diseases.
ALLERGIES
• A hypersensitivity to harmless agents, or
a response in which the immune system
begins to attack normal cells in one’s
own body, can destroy tissues and
organs.
• Allergies occur when your immune
system mistakes harmless cells for
harmful invaders.
• If you are allergic to peanuts, your
immune system recognizes one of the
proteins in the peanut as dangerous.
ALLERGIC RESPONSE
• For allergies to
materials such as dust
mites, pollen, mould
and animal dander, the
reaction of the
antibodies releases
histamines that cause
sneezing, watery eyes
and runny nose.
• Food allergies can be
more severe.
AIDS
• Human Immunodeficiency Virus (HIV) retrovirus that causes AIDS (Acquired
Immunodeficiency Syndrome).
• HIV virus contains one RNA molecule and
two reverse transcriptase molecules.
• After entering the host’s Helper T cell, the
reverse transcriptase triggers the
production of viral DNA (provirus) by the
host nucleus.
AIDS
• The host’s transcribes the viral DNA into
RNA for new viruses resulting in the
destruction of the host cell.
• The destruction of the helper T cells
impedes the discover of pathogens by the
immune system.
• See page 480 of Bio 12 text book .