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The Untold Story. ANTIBODIES. Brought to you by the Flying J’s Jenna Houmes, Julia Coffin, Jennifer Rose, and Jenny Stearman. Presentation Outline. Background Information Structure- Shape, T and B cells, macrophages Function- Interaction with antigens Types of antibodies- 5 types
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The Untold Story ANTIBODIES Brought to you by the Flying J’s Jenna Houmes, Julia Coffin, Jennifer Rose, and Jenny Stearman
Presentation Outline • Background Information • Structure- • Shape, T and B cells, macrophages • Function- • Interaction with antigens • Types of antibodies- • 5 types • Differences • Current studies with antibodies • Allergies • Produce
The Job of an Antibody • Antibodies have been referred to as molecule “watchdogs” • They are always circulating in your blood and investigating every object they come in contact with • Antibodies alarm the rest of the immune system
Chains and Binding Sites Antibodies are made of 4 chains: 2 long, heavy chains (red and orange) 2 shorter light chains (yellow) Binding sites are located at the end of the arms and in between the light and heavy chain. They are made of different lengths and amino acid composition. Each of the binding sites have a different target.
The Importance of Shape • Usually have several flexible arms that each hold a binding site • The arms allow the binding sites to work together in grabbing onto different shaped objects
The Other Guys Involved • Macrophage (gray) • Antigen (orange) • T-Cell ( red sphere riding atop macrophage) • B-Cell (not pictured)
The Immune System • The immune system is the body’s defense mechanism against outside invaders such as viruses and bacteria. The complex components of the system work together to recognize and respond to substances called antigens. An antigen is any substance that, when introduced into the body, is recognized as foreign by the immune system (ex. bacteria or virus). (Antigen)
Components of the Immune System • T cells are immune system cells that help to destroy infected cells and coordinate the overall immune response. The T cell has a molecule on its surface called the T-cell receptor that help T cells recognize antigen fragments. • B cells are the cells that produce antibodies. The B cell can only make antibodies when it receives the appropriate command signal from a T cell • Antibodies binds to an antigen and mark the antigen for destruction by other immune system cells. • Macrophages circulate in the blood and survey the body for foreign substances. When they find foreign antigens (easily identified by the presence of antibodies on the antigen’s surface) they engulf and destroy them. How They Work Together
How they work…. • Antibodies can interlock with toxins to disable them directly (antitoxins). • Other antibodies, by coating bacteria, make the microbes highly palatable to scavenger cells (macrophages) equipped to engulf and destroy them. • Often an antigen-antibody combination unleashes a group of lethal serumenzymes known as complement. • Yet other antibodies block viruses from entering into cells (a quality that is exploited in making vaccines). • And, in a phenomenon known as antibody-dependent cell-mediated cytotoxicity (ADCC),cells coated with antibodies become vulnerable to attack by several types of white blood cells.
ANTIBODY CLASSES: • IgM • IgG • IgD • IgE • IgA
IgM • A pentamer made up of 5 monomers. • First antibody released to the blood by plasma cells in a primary response.
IgG • Y-shaped and a monomer. • Most abundant antibody in the body making up 75%-80% of the antibodies. • Protects against bacteria , viruses, and toxins in the blood and lymph. • Only antibody to cross over the placenta barrier.
IgD • Y-shaped and a monomer. • Always attached to the external surface of a B-cell. • Functions as a antigen receptor of the B-cell. • Important in B cell activation.
IgE • Y-shaped and a monomer. • Rarely found within the blood. • Secreted by plasma cells in skin, tonsils, and mucosa of the gastrointestinal and respiratory tract. • The “troublemaker” antibody: causes cells to release histamine resulting in a allergic reaction.
IgA • Y-shaped and can be either a monomer or a dimer. • Monomer form is minimal in plasma. • Dimer form found in saliva, sweat, intestinal juice, and milk. • Prevents bonding of pathogens to epithelial cell surfaces.
What are allergies? • The result of a immune response in which the immune system causes tissue damage as it fights a perceived “threat” brought on by a antigen that would otherwise be harmless to the body.
Food Allergy Drug Allergy Pet Allergy Insect bites Hay fever Mold, dust, or dander Cosmetics or jewelry TYPES OF ALLERGIES:
WHAT CAUSES AN ALLERGIC REACTION TO OCCUR? • Immune system is exposed to the antigen. - Plasma cells produce a large amount of IgE antibodies. - IgE antibodies attach to mast cells in the body’s tissues.
A mild immune response occurs The immune system is now sensitized to this specific antigen. - This allows the immune system to recognize the antigen if re-exposure occurs.
Second exposure to the antigen: • More of the same antigen invades the body • Antigen combines with IgE attached to mast cells. • This triggers degranulation and release of histamine.
SO… WHAT DOES HISTAMINE DO? • Causes blood vessels to dilate and leak which in turn causes edema. • Stimulates the secretion of mucus, causing smooth muscles to contract (if the respiratory system is the site of the antigen, this can lead to an asthma attack).
Runny nose Increased tearing Itchy nose, throat, mouth, eyes, skin, or any area Wheezing Coughing Difficulty breathing Hives or skin wheals Skin rashes Stomach cramps Vomiting Diarrhea Headache Chemosis and red, itchy eyes HOW CAN YOU TELL IF YOU ARE HAVING AN ALLERGIC REACTION?
Molecular Farming: Antibody Production in Corn • Researchers are currently inserting human genes into corn. • The kernels produce human proteins instead of natural plant proteins. • Surprisingly, this proves to be safer and more easily manufactured than that of the existing antibody production being done in cows, mice, and other animals.
How is this done? • These antibodies would be monoclonal and specific to particular antigens. • Monoclonal antibodies are more sensitive to minute quantities of antigens and therefore useful in detecting antigens such as common allergies, viruses and to a greater extent, diseases such as cancer and AIDS. • This process is so abundant that a 200-acre cornfield could produce enough of the therapeutic proteins in corn plants to manufacture nearly any drug on the market today. • However, investors (both public and private) are still skeptical and pose many economic and ethical concerns.
“Producing a therapeutic protein from plants,” says Robert Dose, vice president of business development at ProdiGene, “instead of standard means like Chinese hamster ovaries, eliminates the risk of the mutant strains of genetically modified organisms people seem to be so worried about.” On the other side, the U.S. Food and Drug Administration along with the Union of Concerned Scientist have concerns related to the environmental impacts and risks to the food supply should a “corn kernel packed with human proteins somehow gets misplaced somewhere along the distribution chain.” (AgiBio World)
In Summation: • Antibodies are integral proteins which aid and assist in the welfare of the body. • Antigens, which are foreign molecules that enter the body, stimulate the release of these antibodies. • For those who have weak immune systems and suffer from common allergies to even life threatening diseases, outside intervention of genetically produced antibodies created within animals and perhaps one day, produce are needed.
References Library.thinkquest.org/3361/media/images/antibody.jpg www.cellsalive.com/antibody.htm Protein Data Bank: http://www.rcsb.org/pdb/molecules/pdb21_1.html Understanding Autoimmune Disease www.niad.nih.gov/publications/autoimmune/autoimmune.htm Understanding the Immune System http://rex.nci.nih.gov/PATIENTS/INFO_TEACHER/bookshelf/NIH_immune/html/imm35.html CELLS Alive! www.cellsalive.com
References MEDLINEplus Medical Encyclopedia: http://www.nlm.nih.gov/medlineplus/ency Biology Pages: http://users.rcn.com/jkimball.ma.ultranet/BiolobyPages/A/ AgBio World http://www.agbioworld.org/biotech_info/articles/interviews/protein_therapy.html Marieb, Elaine N., Human Anatomy and Physiology. 5th edition. San Francisco: Benjamin Cummings, 2001. Howard, Gary C., Delia, R. Bethell, Basic Methods In Antibody Production and Characterization. Boca Raton: CRC Press, 2000.