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Immune Defenses
SBI 4UI
Mrs. Tuma
What is immunity?
What is immunity?
O - a variety of white blood cells and proteins
that attack foreign invaders such as bacteria
and viruses
O - immunity is the ability to resist a disease
after being exposed to the disease in the
past
http://medical-dictionary.thefreedictionary.com
Non-Specific Defenses:
-guard against a wide variety of pathogens
-does not depend on prior exposure to the pathogen
O Skin
O Body Secretions
e.g.: saliva, tears, stomach acid, urine
O Normal flora
O White Blood Cells
- Natural Killer cells, macrophages, dendritic cells
Specific Defenses of the Body:
O recognize foreign substances and act to destroy or
neutralize them
O specific immune defence is a function of Lymphocytes
O Two types:
- B lymphocytes (B cells): mature in bone marrow
- T lymphocytes (T cells): mature in thymus gland
O Lymphoid organs - tonsils, appendix, bone marrow,
lymphatic system, thymus glands etc.
How does it work?
[*Antigen = any protein that stimulates an immune response]
Pathogen or antigen*
Macrophages engulf &
display surface antigens
stimulates helper T cells
cytotoxic T cellls
memory T cells
Active cytotoxic T cells
B Plasma Cells
*Make antibodies
B Memory cells
*Remember how to make
antibodies
* make cytokines
* kill cells via chemical
warfare
http://www.uic.edu/classes/bios/bios100/lectures/immune.htm
What about transplantation?
Tissue typing
- blood types must match (A, B, AB, O)
- proteins on cells called (Major Histocompatibility
Complex) MHC markers must match closely
Rejection
- give anti-rejection drugs (a reality!)
- some serious side effects
What about transplantation?
Graft-versus-host disease
- seen in bone marrow transplants with
leukemia patients
- patient's own cells are wiped out by radiation and
chemotherapy
- transplanted cells start to attack the recipient
- try to prevent by closely matching recipients cell
protein markers
What about vaccination?
O weakened/dead form of bacteria/virus or some of
its surface proteins
O usually injected, but some oral (e.g. polio)
O immune system will make antibodies against the
antigen and memory cells are stimulated
O on second exposure, memory cells can stimulate
antibody production very quickly
What about vaccination?
Examples of Common Vaccines:
O DPTP
O MMR
O Chicken Pox
O Meningitis
O HPV