How does specific immunity work

Activating the complement system Complement System One of the body's lines of defense immune system involves white blood cells leukocytes that travel through the bloodstream and into tissues, searching for and attacking microorganisms and Antibodies are essential for fighting off certain types of bacterial and fungal infections. They can also help fight viruses. Antibodies attach to the antigen they were formed to recognize and form an immune complex antibody-antigen complex.

The antibody and antigen fit tightly together, like pieces of a jigsaw puzzle. Sometimes an antibody can attach to other antigens if the antigens closely resemble the antigen that the antibody was formed to recognize and attach to.

Variable part: This part varies from antibody to antibody, depending on which antigen the antibody targets. The antigen attaches to the variable part. This part is the same within each class. This part is the same within each class and determines the function of the antibody. An antibody can switch its constant part and become a different class, but its variable part does not change.

Thus, it can always recognize the specific antigen that it was formed to attach to. This class of antibody is produced when a particular antigen such as an antigen of an infectious microorganism is encountered for the first time. The response triggered by the first encounter with an antigen is the primary immune response.

IgM then attaches to the antigen, activating the complement system, and thus makes the microorganism easier to ingest.

IgG, the most prevalent class of antibody, is produced when a particular antigen is encountered again. More antibody is produced in this response called the secondary immune response than in the primary immune response. The secondary immune response is also faster and the antibodies produced—mainly IgG—are more effective.

IgG is present in the bloodstream and tissues. It is the only class of antibody that crosses the placenta from mother to fetus. Also, IgG is the most common class of antibody used in treatment. For example, immune globulin antibodies obtained from the blood of people with a normal immune system consists mainly of IgG.

Immune globulin is used to treat some immunodeficiency disorders Overview of Immunodeficiency Disorders Immunodeficiency disorders involve malfunction of the immune system, resulting in infections that develop and recur more frequently, are more severe, and last longer than usual. These antibodies help defend against the invasion of microorganisms through body surfaces lined with a mucous membrane, including those of the nose, eyes, lungs, and digestive tract.

Colostrum the fluid produced by the breasts during the first few days after delivery, before breast milk is produced. These antibodies trigger immediate allergic reactions Overview of Allergic Reactions Allergic reactions hypersensitivity reactions are inappropriate responses of the immune system to a normally harmless substance. Usually, allergies make people sneeze; the eyes water and itch IgE binds to basophils Basophils One of the body's lines of defense immune system involves white blood cells leukocytes that travel through the bloodstream and into tissues, searching for and attacking microorganisms and When basophils or mast cells with IgE bound to them encounter allergens antigens that cause allergic reactions , they release substances such as histamine that cause inflammation and damage surrounding tissues.

Thus, IgE is the only class of antibody that often seems to do more harm than good. However, IgE helps defend against certain parasitic infections that are common in some developing countries.

Small amounts of IgE are present in the bloodstream and mucus of the digestive system. These amounts are higher in people with asthma, hay fever, other allergic disorders, or parasitic infections. Small amounts of these antibodies are present in the bloodstream.

Their function in the bloodstream, if any, is not well understood. The main roles of the lymphatic system are to: manage the fluid levels in the body react to bacteria deal with cancer cells deal with cell products that otherwise would result in disease or disorders absorb some of the fats in our diet from the intestine.

The lymphatic system is made up of: lymph nodes also called lymph glands -- which trap microbes lymph vessels -- tubes that carry lymph, the colourless fluid that bathes your body's tissues and contains infection-fighting white blood cells white blood cells lymphocytes. Spleen The spleen is a blood-filtering organ that removes microbes and destroys old or damaged red blood cells.

Bone marrow Bone marrow is the spongy tissue found inside your bones. Thymus The thymus filters and monitors your blood content. The body's other defences against microbes As well as the immune system, the body has several other ways to defend itself against microbes, including: skin - a waterproof barrier that secretes oil with bacteria-killing properties lungs - mucous in the lungs phlegm traps foreign particles, and small hairs cilia wave the mucous upwards so it can be coughed out digestive tract - the mucous lining contains antibodies, and the acid in the stomach can kill most microbes other defences - body fluids like skin oil, saliva and tears contain anti-bacterial enzymes that help reduce the risk of infection.

The constant flushing of the urinary tract and the bowel also helps. Fever is an immune system response A rise in body temperature, or fever , can happen with some infections. Common disorders of the immune system It is common for people to have an over- or underactive immune system.

Overactivity of the immune system can take many forms, including: allergic diseases - where the immune system makes an overly strong response to allergens. Allergic diseases are very common. They include allergies to foods, medications or stinging insects, anaphylaxis life-threatening allergy , hay fever allergic rhinitis , sinus disease, asthma, hives urticaria , dermatitis and eczema autoimmune diseases - where the immune system mounts a response against normal components of the body.

Autoimmune diseases range from common to rare. They include multiple sclerosis, autoimmune thyroid disease, type 1 diabetes, systemic lupus erythematosus, rheumatoid arthritis and systemic vasculitis.

Immunoglobulin therapy Immunoglobulins commonly known as antibodies are used to treat people who are unable to make enough of their own, or whose antibodies do not work properly.

Immunisation Immunisation works by copying the body's natural immune response. Together, these factors are referred to as HALO, which is defined as: health - some health conditions or factors may make you more vulnerable to vaccine-preventable diseases.

For example, premature birth, asthma, diabetes, heart, lung, spleen or kidney conditions, Down syndrome and HIV will mean you may benefit from additional or more frequent immunisations age - at different ages you need protection from different vaccine-preventable diseases.

Australia's National Immunisation Program sets out recommended immunisations for babies, children, older people and other people at risk, such as Aboriginal and Torres Strait Islanders.

Most recommended vaccines are available at no cost to these groups lifestyle - lifestyle choices can have an impact on your immunisation needs. Travelling overseas to certain places, planning a family, sexual activity, smoking, and playing contact sport that may expose you directly to someone else's blood, will mean you may benefit from additional or more frequent immunisations occupation - you are likely to need extra immunisations, or need to have them more often, if you work in an occupation that exposes you to vaccine-preventable diseases or puts you into contact with people who are more susceptible to problems from vaccine-preventable diseases such as babies or young children, pregnant women, the elderly, and people with chronic or acute health conditions.

For example, if you work in aged care, childcare, healthcare, emergency services or sewerage repair and maintenance, discuss your immunisation needs with your doctor. Some employers help with the cost of relevant vaccinations for their employees.

IDFA More information here. Give feedback about this page. Was this page helpful? Yes No. But after the first exposure, the immune system will recognize the invader and defend against it. The acquired immune system changes throughout your child's life. Immunizations train your child's immune system to make antibodies to protect him or her from harmful diseases. Lymph nodes. Small organs shaped like beans, which are located throughout the body and connect via the lymphatic vessels.

Lymphatic vessels. A network of channels throughout the body that carries lymphocytes to the lymphoid organs and bloodstream. Antibiotics can be used to help your child's immune system fight infections by bacteria. Antibiotics were developed to kill or disable specific bacteria. That means that an antibiotic that works for a skin infection may not work to cure diarrhea caused by bacteria.

When the body senses foreign substances called antigens , the immune system works to recognize the antigens and get rid of them. B lymphocytes are triggered to make antibodies also called immunoglobulins.

These proteins lock onto specific antigens. After they're made, antibodies usually stay in our bodies in case we have to fight the same germ again. That's why someone who gets sick with a disease, like chickenpox, usually won't get sick from it again. This is also how immunizations vaccines prevent some diseases. An immunization introduces the body to an antigen in a way that doesn't make someone sick. But it does let the body make antibodies that will protect the person from future attack by the germ.

Although antibodies can recognize an antigen and lock onto it, they can't destroy it without help. That's the job of the T cells.