- FIRST LINE OF DEFENSE.
- ORGANS AND TISSUES INVOLVED IN THE
IMMUNE RESPONSE.
- ANTIGENS AND THE MAJOR
HISTOCOMPATIBILITY COMPLEX.
- SELF AND NON SELF.
Melissa &
Ralph.

- To develop an understanding of how the body protects itself from disease, the immune response, antigens and the major histocompatibility complex.
- To understand the concept of ‘self’ and ‘non self’.

 - What makes up the first line of defense?
- Which organs and tissues are involved with the immune response?
- Where are antigens found and what do they do?
- What is the Major Histocompatibility Complex?
- How does the body detect self from non self?
- True or False. Bacteria can help the human body by out-competing other bacteria.
 - True or False. Plants are incapable of releasing chemicals to ward off pathogen. They only rely on stomatal closing and cell wall.
 - True or False. Mucus makes you sick.
 - Can you give us an example of a lymphoid organ?
 - What do we know about the appendix?
 - Do we know which biomacromolecule makes up antigens?


 The skin is considered as the largest organ in the human body which protects us from pathogens and other harmful substances.
 The skin is a dry and does not contain any holes (apart from pores).
 A breach in the surface of the skin would allow opportunistic pathogens to enter the bloodstream and circulate around the body.

 The respiratory tract also releases mucous that envelops bacteria.
 It is a water-based liquid that contains proteins, carbohydrates, salt and some cells
 Some are swallowed while others are projected away via coughing or sneezing.
 This protects us from airborne bacteria

 The body is capable of releasing chemicals that can counteract pathogens.
 The nature of these chemicals is enough to restrain, if not kill the invading pathogen.
 They differ from antigens though, for they are a type of non-specific immune response; meaning they are important for different matters but can be also help with immune system.

 The body acts as host to some good bacteria. Together, they work in unison to benefit one another.
 These good bacteria out-competes pathogen in terms of nutrition and space available.

 Cuticle and cell wall – These structures provide a thick barrier for plants, making it difficult for pathogens to penetrate and infest the plant.
 Waxy cuticle – The waxy cuticle prevents formation of moisture films on leaf surfaces.
 Lenticels
 Stomata – Narrow stomatal opening limits bacterial infestation.

 Phytoanticipins – Inhibits the growth of pathogen.
 Plant defensins – This protein inhibit pathogens such as fungi, virus, bacteria and insects nutrition and retard their development.
 Nutrient Deprivation
 Changing leaf surface pH.

 An immune response is the body’s way of detecting and defending itself from potentially harmful foreign organisms or substances.
 The collection of organs and tissues involved with immune response is collectively known as the ‘Lymphoid
System’
 These organs are responsible for the growth, development and the release of special cells called
‘lymphocytes’ which kills pathogens.

 Adenoids are lumpy clusters of spongy tissue that is located at the back of the nasal cavity and are above the roof of the mouth.
 This tissue is responsible for trapping harmful bacteria and viruses the we breathe in or swallow.

 The appendix is a small tube that is connected to our large intestine.
 Although most people in the medical profession consider this organ to be ‘useless’, this organ actually assists in the maturation of B lymphocytes and in the production of the class of antibodies known as immunoglobulin A antibodies.

 The bone marrow is a soft, fatty tissue found in bone cavities.
 A special type of tissue that produces important cells such as B cells, natural killer cells, granulocytes and immature thymocytes, in addition to red blood cells and platelets.

 These are tiny bean-like organs located throughout the body is connected by lymph vessels.
 These nodes function as an ‘immunologic’ filter for the bodily fluid known as lymph.

 This serves as the main highway for the lymphocytes
 Lymphatic vessels are responsible for draining interstitial fluid from tissues and for transporting immune cells to lymph nodes to maintain the body’s immune surveillance.

 Is a fist-sized organ located at the abdominal cavity.
 This organ serves as an immunologic blood filter of the body.

 This is a lymphoid tissue found in the small intestine.
 This tissue interacts with antigens found in the intestine to produce antibodies.

 The thymus are two lobes that join in front of the trachea behind the breast bone.
 This organ is responsible for producing T-cells.

 The tonsils are two oval masses located in the back of the throat.
 The tonsils are like the adenoids, they help the body by trapping harmful bacteria and viruses the we breathe in or swallow.

ANTIGENS: Any substance foreign to the body that triggers a response from the immune system, such as producing antibodies in order to neutralise it.
- Also known as immunogens
- Usually made up of proteins but can be polysaccharides
- Found on the surface of all cells, called self antigens or auto antigens
- All have unique shapes
- A way to remember: anti gen s = anti body gen erators
- Antibodies are generated to attack the pathogen behind the antigen being detected

http://www.youtube.com/watch?v=Ys_V6FcYD5I

Human blood can be classified as:
- Rhesus positive (Rh+)
- Rhesus negative (Rh-)
Rh+
Does have the D antigen on cells
Rh-
Doesn’t have the D antigen on cells
- Significant during pregnancy
- If mother and baby are opposite in regards to Rhesus, they’re incompatible
- Could result in fatality for the baby
- Treated by mother being given injections of the D antigen, also referred to as Anti-D.

SELF: agents belonging to the individual
NON SELF: agents belonging to another organism or person (foreign)
- All cells in the body have ‘marker proteins’ on the surface, like a chemical signature
- There markers carry genetic information
- If the genes on a cells plasma membrane match the individual’s genes, the cell is marked as ‘self ’ and is then ignored by the B and T cells
- If the genes on a cell’s plasma membrane don’t match the individual’s genes, the cell is marked as ‘non self’
- The system which sorts ‘self’ and ‘non self’ cells, is called the MAJOR HISTOCOMPATIBILITY COMPLEX

THE MAJOR HISTOCOMPATIBILITY COMPLEX (MHC) – a genetic system which allows large proteins in the immune system’s cells to identify compatible and foreign agents.
- Also known as Human Leukocyte Antigen
- The MHC distinguishes ‘self’ from ‘non self’
- Plays a key role in immunity
- Everyone’s MHC markers are unique as no two individuals have the exact same genetic information
- 2 types: MHC class I and MHC class II
- MHC class I markers: found on all cells that have a nucleus, except red blood cells
- MHC class II markers: found on antigen presenting cells, such as macrophages

TRANSPLANTS AND BLOOD TRANSFUSIONS.
How does the body accept a new heart or some new blood when it doesn’t hold the same genetic information?
How is rejection avoided?
- Blood and tissue tests are carried out to help in choosing an organ or blood with the most similar genetic information
- Immunosuppressant's
- Stem cell and/or bone marrow transplants at the same time

 - What makes up the first line of defense?
- Which organs and tissues are involved with the immune response?
- Where are antigens found and what do they do?
- What is the Major Histocompatibility Complex?
- How does the body detect self from non self?
- True or False. Bacteria can help the human body by out-competing other bacteria.
 - True or False. Plants are incapable of releasing chemicals to ward off pathogen. They only rely on stomatal closing and cell wall.
 - True or False. Mucus makes you sick.
 - Can you give us an example of a lymphoid organ?
 - What do we know about the appendix?
 - Do we know which biomacromolecule makes up antigens?

- What’s something interesting you learnt today?
- Is there anything you still don’t understand?
QUICK CHECK 1, 3
CHAPTER REVIEW 5, 7, 8
CROSSWORD

 Y ear 12 Bi ology Textbook
 Nelson Bi ology Uni ts 3&4 – Semple, Borger, Cotton, Duncan, Cunni ngham,
Jackel
 BI OL notes – Di ane Canavan
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 http://kidshealth.org/kid/ill_injure/sick/adenoids.html
 http://medicalcenter.osu.edu/patientcare/healthcare_services/infectious_diseases/imm unesystem/pages/index.aspx
 http://www.scientificamerican.com/article.cfm?id=what -is-the-function-of-t
 http://www.thebody.com/content/art1788.html
 http://www.medicinenet.com/adenoids_and_tonsils/article.htm
 http://steele.mgh.harvard.edu/main/index.php?option=com_content&view=category&l ayout=blog&id=3&Itemid=29http://www.wisegeek.com/what-is-an-antigen.htm
 http://njaffee.wordpress.com/
 http://www.britannica.com/EBchecked/topic/359034/major
 histocompatibility-complex-MHC
 http://www.healthline.com/galecontent/major-histocompatibility-complex
 http://www.webbooks.com/eLibrary/Medicine/Physiology/Immune/Antigen.htm
 http://thyroid.about.com/library/immune/blimm02.htm
 http://health.org/parent/general/body_basics/immune.html
 http://www.elasmo-research.org/education/white_shark/immunology.htm
 http://www.niaid.nih.gov/topics/immuneSystem/pages/selfnonself.aspx
 http://www.popularmechanics.com/science/health/life -extension/4343954
 http://otah2o.wikispaces.com/05+Hematology