The immune system protects the body from pathogens through a variety of cells and processes. It has both innate defenses like skin, mucus, and stomach acid, as well as adaptive responses mediated by B cells, T cells, macrophages, and natural killer cells. The adaptive immune response involves activation of T cells by antigen-presenting cells, proliferation of effector T cells, and the creation of memory T cells. Immunizations boost immunity by training the immune system to recognize pathogens without causing disease.

1. The Mighty Immune
System
The immune system is our body's defense against harmful pathogens like
bacteria and viruses. Learn about how our immune system works and the
different types of immune cells that play a role in keeping us healthy.
by Hussain Taqi

2. The First Line of Defense
Skin Barrier
The skin acts as a barrier to prevent
harmful pathogens from entering the
body.
Mucous Membrane
The mucous membrane traps pathogens
that enter through the nose and mouth.
Stomach Acid
The acidic environment in the stomach
kills many harmful pathogens.

3. Behind the Scenes
B cells
B cells create antibodies that bind to
specific pathogens and mark them
for destruction by other immune
cells.
T cells
T cells recognize and attack infected
cells, preventing the infection from
spreading.
Macrophages
Macrophages can engulf and destroy
pathogens through a process called
phagocytosis.
Natural Killer Cells
Natural killer cells are essential in detecting and destroying virally-infected cells and even tumor cells.

4. Adaptive Immune Response
1 Activation
Antigen-presenting cells like dendritic cells activate T
cells by presenting them with pieces of the pathogen.
2
Proliferation
Activated T cells proliferate and differentiate into
effector T cells, which destroy infected cells.
3 Memory
Some effector T cells remain as memory T cells that
can rapidly respond to the same pathogen in the
future.

5. Humoral Immunity
Plasma Cells
Activated B cells differentiate into plasma
cells that secrete large quantities of
antibodies into the bloodstream.
Antibodies
Some antibodies directly neutralize
pathogens, while others mark them for
destruction by other immune cells.
Memory B Cells
Memory B cells can rapidly produce
antibodies in response to the same
pathogen in the future.

6. Immunodeficiency Disorders
1 HIV/AIDS
HIV infects and kills T cells,
weakening the immune
system and making it more
susceptible to other
infections.
2 SCID
SCID is a rare genetic
disorder that results in a
severely weakened immune
system, leaving the
individual vulnerable to life-
threatening infections.
3 Cancer
Cancer cells can disrupt the immune system by producing
substances that suppress immune cells or by hiding from the immune
system.

7. Immune System Boosters
Eat Well
A healthy diet rich in fruits and
vegetables can provide the body with
essential vitamins and minerals that
support immune function.
Exercise Regularly
Regular physical activity can help
reduce the risk of chronic diseases and
strengthen the immune system.
Reduce Stress
Stress can weaken the immune system,
so find ways to manage stress through
techniques like meditation or yoga.

8. Immunizations
Benefits
Immunizations can protect
individuals from serious and even
deadly infections by training the
immune system to recognize and
fight specific pathogens.
Herd Immunity
When a significant proportion of the
population is immunized against a
pathogen, it can prevent the
pathogen from circulating and protect
even those who cannot receive
certain vaccines.
Risks
Vaccines can cause side effects, but
serious or life-threatening reactions
are rare.