IMMUNOLOGY: is the branch of biomedical science which studies the structure and function of the immune system. It can be broken down into Clinical Immunology: which includes immunizations, organ transplantation, blood banking and immunopathology. Laboratory Immunology: which includes laboratory testing of cellular and humoral immune functions. Serology and Immunochemistry: uses of antigen-antibody reactions in other laboratory tests.
Definition from Miller-Keane Encyclopedia & Dictionary or Medicine, Nursing & Allied Health, 5th Edition.

The immune system has many different defense mechanisms which help our body to fight off unwanted pathogens.
B Lymphocytes secrete antibodies which will bind to a specific antigen either killing the cells that contain the antigen or promote phagocytosis. There are two different T Lymphocytes, killer T cells and helper T cells. Active and passive immunity also play an important role in how our body is able to fight off diseases. Cells can be cloned so that the next time the same pathogen tries to infect the body the immune response will be stronger and able to fight it off—active immunity. Passive immunity is when there is a transfer of antibodies to recipient from a human or animal donor. There is also tumor immunology where the cells are actually fighting off cells that can become cancerous. As we all know not everything is perfect, our immune system can cause disease without having an invading pathogen.

This is a short video on the Immune System Response. Please View.
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Antigen: a cell or protein that your body did not make itself, so it thinks it is foreign and will try to fight it off.

B lymphocytes are created in the bone marrow. There are antibodies on the surface of B-cells that are receptors for a specific antigen. Their function is to make antibodies which attach to certain antigens, making the antigen inactive so it is unable to to attach to a cell and take it over. B cells will divide several times some will become memory cells and other will become plasma cells. The memory cells will travel around our blood and lymphatic system and if they come in contact with the same pathogen again they will be able to produce antibodies faster to help fight off the infection. B lymphocytes kill at a distance by secreting antibodies. These cells are able to live for a long time. Plasma cells, which are protein factories, can produce 2000 antibodies a second that are specific for the original antigen. This provides active immunity.


Antibodies: are immunoglobulin proteins, which the B lymphocytes secrete, have been transformed into plasma cells. Antibodies are responsible for humoral immunity. These are part of the Gamma Globulin class of plasma proteins. They have the same basic structure (Y). They have two long, heavy (H) chains which are joined to two shorter, light (L) chains. There are about 100 million trillion antibody molecules in each one of us. Hopefully there is an antibody specific for any antigen a person might encounter.

IgG -- Main form of antibodies in circulation. Production increased after immunization. Secreted during secondary response.
IgA-- Main antibody in external secretions. Saliva and mother’s milk
IgE-- Responsible for allergic symptoms.
IgM -- Largest antibodies in our system. Before immunization. Secreted during primary response
IgD-- Found in blood and lymph. Before immunizations. Other functions unknown

This information was taken from our book, Human Physiology, Stuart Ira Fox, 12th Edition, Page 497.

THE COMPLEMENT SYSTEM: is a series of proteins floating in our blood. These proteins are manufactured in the liver.
Antibodies and antigens together do not destroy the pathogens that are present. The antibodies identify the targets for attack which activate nonspecific immune processes to destroy the pathogen. The compliment proteins are activated and will work with the antibodies to cause lysing of cells and to signal phagocytes to the cells that need to be removed. There is the classic pathway which triggers the binding of the antibodies to the antigens. The alternative pathway is a unique polysaccharide coating of bacteria.

T LYPMOHOCYTES: Killer, Helper and Regulatory

T lymphocyte, SEM
T lymphocyte, SEM

KILLER: Carry CD8 surface markers. Their function is to destroy body cells that harbor foreign molecules. In order to kill the victim cells, they must be in actual physical contact with the cells; this is called cell-mediated destruction. This happens by the secretion of molecules called Perforins which create a pore in the membrane and cause lysis of the cell and enzymes called Granzymes which cause destruction of the cell's DNA. Killer T cells will defend against viral and fungal infections, are responsible for transplant rejection reactions and for immunological surveillance against cancer. When it comes to organ transplants, the donor's organs need to be composed of tissue that match the tissue of the recipient. The MHC (major histocompatibility, which are on the surface of the T-cells) proteins determine the "match". If they do not match the T-cells in the recipient may think the donor tissue is foreign (an antigen) and start to attack the organ.

HELPER: They have no cytotoxic or phagoctyic activities and do not secrete antibodies. They cannot kill an infected cell on their own, they need to activate and direct other immune cells. Helper T-cells carry CD4 surface markers. They are very important in the immune system. Diversified in function and play an important role in influencing other cells; they enhance the responses of the killer T-cells and B-cells.

REGULATORY: Will decrease the responses of the killer T-cells and B-cells. They carry CD25 and CD4 surface markers. They help to protect against autoimmune responses including allergy and autoimmune diseases. These cells need to be close to its victim cell or even have physical contact with the cell. They may release cytokines, granzymes or perforins. Some regulatory T-cells may get recruited by certan viral infections or cancers to protect themselves from an immunological attack. This may happen when there is a vigorous functioning of the regulatory T-cells.

Oncoloy: the study of tumors. Benign Tumors: slow growing and limited to a specific location. Malignant Tumors: grow more rapidly and undergo metastasis-cells have moved into different parts of the body from where it first started. Cancer: malignant tumors.

Two natural killer cells attack a cancer cell - Graphic  Eye on Science/Photo Researchers.Inc.
Two natural killer cells attack a cancer cell - Graphic Eye on Science/Photo Researchers.Inc.

The immune system also is used to identify and eliminate tumor cells. The antigens that are found on a tumor cell are different from normal cells. So when the immune system sees these antigens as foreign, this causes the immune cells to attack the transformed tumor cells. Killer T-cells are called into action to destroy the cancer cells. Sometimes the Helper T-cells are also needed to help eliminate the abnormal cells. Tumor cells can be very smart. They can avoid detection by releasing products that inhibit the immune response. In the 1970's the concept of immunological surveillance was introduced. It states that we all have tumor cells which appear often in our bodies. These cells are normally recognized and destroyed by the immune system before they can cause cancer. Just like everything else in life, nothing is perfect some of the tumor cells get through and start to reproduce. As we age, things start to wear out, including our immune system, it becomes harder for the lymphocytes to fight off the pathogens. The doctor I work for states that if we live long enough we are all going to have some type of cancer.

I thought this was an interesting version on Killer Cells vs Tumor Cells. It is 3 minutes long, good animation!
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Autoimmune diseases are those produced by failure of the immune system to recognize and tolerate self-antigens. They can arise from having an overactive immune response against a substance or tissues normally present in the body. The body attacks itself because it is thinking some part of the body is a pathogen.

Diseases caused by the immune system include: Rheumatoid arthritis, type 1 diabetes mellitus, multiple sclerosis, Graves’ disease, pernicious anemia, psoriasis and lupus.

The symptoms of an autoimmune disease vary depending on the disease as well as the person’s immune system.
Common symptoms include: inflammation, fatigue, dizziness, muscle aches or stiffness, fever, sensitivity to cold in the hands and feet, weakness, weight changes, a person may become more irritable and there could be a change in size or destruction of an organ or tissue in the body.

WebMD, Multiple Sclerosis, slide show: A visual Guide to MS
WebMD, Multiple Sclerosis, slide show: A visual Guide to MS

Multiple Sclerosis
It is a chronic disease that damages the nerves in the spinal cord and brain. The myelin sheath is what is destroyed and not the nerve cells themselves. With the destruction of the myelin sheath the nerve impulses have trouble getting from one area to the next. It also affects the optic nerve causing the patient to have trouble with their sight, including blurred vision, loss of color vision, eye pain or blindness. These symptoms usually affect only one eye and the problem is temporary with improvement seen in a couple of weeks. This is usually why the patients are seeking medical advice and is the first sign of MS. People with this disease develop several areas with scarring of tissue because of the nerve damage that has happened. Symptoms can include balance difficulty, loss of muscle control, vision problems and trouble with speech.

The course of MS can be long with remissions and relapses over a period of years. It is not known exactly how people develop MS. Many physicians feel that a viral infection plays some role in the disease process and that an inherited immune response is somehow responsible for the production of autoantibodies that attack the myelin sheath. It is hard to diagnose MS because of all the symptoms that present and the possibility of it being some other neurological disorder. It tends to hit people between the ages of 20 and 40 years old, does not discriminate and happens in climates that have major temperature changes. Stress can aggravate the condition and precipitate a flare-up of symptoms. The patient needs support and encouragement, plenty of rest and exercise, eat a well balanced diet, avoid sources of infection and stress. There are medicines also available to help with the symptoms, these are not always cheap. Not only the patient but family members also need support and encouragement from friends and family. Having other victims of MS to communicate with also helps.

APPLICATION: With working in the clinic, for 13 years, I have given a lot of injections to both children and adults. To me it is a no brainer, get your child vaccinated. These vaccinations have been developed to protect our children from some terrible diseases. I remember while growing up seeing pictures of kids and adults with polio, they were crippled. No one sees those pictures these days because very few people get polio here in the United States. This is because we have the Polio vaccine and children have been immunized. The vaccination for chicken pox (Varicella) was just starting to be given to children when I started working at the clinic. Parents were given the choice to wait to see if their child would get the disease before giving them the immunization. Most children have received the immunization and we very rarely see or hear about a break out of chicken pox. When my kids had the chicken pox one started and a week later the other one got it. Thank goodness for my mother who was able stay with them during the day so I didn’t miss any work. Many parents do not have the luxury of having a grandparent so close to help out, plus they cannot afford to miss as much as 2 weeks from work, kids cannot go do daycare or school until all the pox are scabbed over.

Vaccines have changed several times over the years, going from giving one vaccine at a time (Polio which is abbreviated IPV) to having the vaccines in a combination injection(DTaP, IPV, Hib), which saves the child a couple pokes. Here is South Dakota children are required to have a certain number of immunizations before entering school. Children need 5 doses of DTaP, 4 doses of IPV, 2 doses of MMR, 2 doses of Varicella, and 4 doses of Hib. There are a few other vaccinations that are not required by the school but the state recommends, these being Prevnar and Rotovirus. The state has done a good job by having the immunizations free to the children to make it easier for parents to get their children immunized. But there are getting to be more and more parents who feel that they are “better educated” with having the internet at their disposal, that do not feel it is necessary to immunize their children. Dr. Dan had a mother who brought her 2 month old in for a well child check. Dr. Dan starts to talk about immunizations and she makes this statement about “being better educated” and not going to give him any shots. She had three older children and they all had their immunizations but she is better educated now so this little one wasn’t going to get any immunizations. She is planning on home schooling this child so he will not need them to get into school. My question to her would be are you going to keep him in a bubble or is he going to be able to live life. All it is going to take is for a few more parents to think like this parent and we could start seeing more outbreaks of different childhood diseases. Why put your child through a disease when all it takes to keep the child healthier is an injection.

Polio Facts from the CDC

Essentional Question
Active Immunity vs Passive Immunity:
Active immunity is having prior exposure to specific antigens. When a child gets the chicken pox he/she will be immuned to getting them as an adult. A primary response has been started. This is a naturally acquired immunity. Getting vaccinations exposes the body to the pathogen and stimulates a primary response against the antigen without causing the disease. This is an artificial acquired immunity. Both of these immunities will produce immunological memories so if the pathogen is introduced into the body again the body will be ready to fight it off. The duration of resistance can last for years.

Passive immunity is the process of transferring antibodies to a recipient from a human or animal donor. The donor has already been actively immunized. A mother can pass immunity onto her fetus during pregnancy and while she is nursing her baby through the colostrum and breast milk. It takes about a month after birth to have immunological competence, which is the ability to have a specific immune response. Tetanus, hepatitis, rabies and snake venom are passive immunizations that are used to protect people who have been exposed to an infection or toxin. These immunizations will need to be repeated. With Tetanus, it is good for 10 years unless the person has a laceration or steps on a rusty nail after 5 years, then the immunization is repeated at the time of the injury.

Innate Immunity vs Adaptive immunity
Innate immunity provides immediate defense against an infection but it is not a long lasting or a protective type of immunity. Structures that are considered part of the innate immunity include the skin, which gives a physical barrier to protect the body from pathogens. The digestive tract because there is a high acid content in the stomach and the normal bacterial that reside in the colon. The respiratory tract has all the cilia moving the mucus. The genitourinary tract has the urine which contains acid and the vaginal lactic acid. Within the body there are the phagocytes which are ingesting and destroying bacteria. Interferons inhibit replication of viruses along with the natural killer cells which destroy the cells that have become infected with viruses and tumor cells.

Adaptive immunity is the body’s way of preparing itself for future challenges. There are special features of the pathogens that the phagocytes will recognize. This is not an inherited trait. The lymphocytes change over the years to stay ahead of the pathogens. They adapt so they can recognize and remember specific pathogens and to have the ability to provide a stronger attack each time the pathogen is encountered.

Cell-Mediated Immunity vs Homoral Immunity
Cell-mediated immunity does not involve the use of antibodies but will activate T-cells, macrophages and natural killer cells to respond to pathogens. The CD4 cells and helper T cells are the ones that provide the protection from the pathogens. How the T-cells work is that they cause apoptosis, death of the infected cells. Cytokines are secreted to influence other cells in the adaptive and innate immune responses. This type of immunity works best with removing virus infected cells but also plays a major role in transplant rejection.

Humoral immunity is provided by the B lymphocytes in the blood and lymph fluids. The B cells transform into plasma cells and secrete antibodies which will bind with the antigen on the surface of the invading pathogens. The pathogen is now flagged to be destroyed.

Describe the process of a local inflammatory response.
Process of inflammation includes antigens on the surface of bacterial cells which bind to antibodies. This activates neutrophils which arrive first to the infected area. The neutrophils and macrophages start to engulf the bacteria. They release chemicals to recruit monocytes, lymphocytes and other immune cells. The complement system stimulates mast cells to release histamine. This causes dilation of the capillaries so a large amount of blood can pass through. With all the blood supply coming to the area it makes the area look red. The more blood that flows to the area the more new phagocytic leukocytes are brought to the site to help fight off any infection. Any extra tissue fluid that is brought to the site also helps to flush out any sources of potential infection, with this happening the area starts to swell. Pus is created by the accumulation of dead leukocytes. Without inflammation, wounds and infections would not heal.

Signs and symptoms of inflammation would include swelling around the area, redness, area is warm to the touch, fever, drainage from the site.

All information for this page came from: our book, Human Physiology, Stuart Ira Fox, 12th Edition, Miller-Keane Encyclopedia & dictionary of Medicine, Nursing, & Allied Health, 5th Edition. Discovery Health web site. WebMD web site,, Anatomy & Physiology for Dummies by Donna Rae Siegried, and the other web sites that are listed with the pictures and videos.