Session 3: Prevention and Treatment Flashcards
What is passive naturally acquired immunity?
Antibodies pass from the mother to the fetus via the placenta during pregnancy or to her infant through her milk. The infant’s body does not produce any antibodies of its own. This kind of immunity is referred to as the transfer of anitbodies from one individual to another.
What is active naturally acquired immunity?
When the body makes its own antibodies. This kind of immunity is acquired from exposure to the disease organism through infection with the actual disease (exposing an individual to an antigen to generate an adaptive immune response). Antigens can enter the body naturally when infection by microbes causes full expression of the disease and/or a sub-clinical infection (one with no obvious symptoms). The body produces specialized lymphocytes and antibodies against the target pathogen.
What is passive artificially acquired immunity?
Preformed antibodies in an immune serum are introduced into the body by injection (e.g. anti-venom, monoclonal antibodies). The body does not produce any antibodies but receives them passively.
What is active artificially acquired immunity?
Antigens (weakened or dead microbes or their fragments) are introduced in vaccines. The body then makes specific lymphocytes and antibodies.
Describe vaccine.
A vaccine is a suspension of microorganisms (or pieces of them) deliberately introduced into the body to protect against disease. It induces immunity by stimulating the production of antibodies. There are two basic types of vaccines, sub-unit vaccines and whole-agent vaccines. Whole-agent vaccines contain whole, nonvirulent microorganisms: inactivated (killed) by formalin or other chemicals, or attenuated viruses (weakened but can mutate into virulent form). Sub-unit vaccines contain some part or product of the microorganisms that can produce an immune response. There are four main types: pathogen proteins (produced by genetically engineered yeasts), bacterial toxins (inactivated by heat), conjugated vaccines (part of various pathogens are combined), or fragments of the pathogen.
What is a monoclonal antibody?
A monoclonal antibody is an artificially produced antibody that neutralizes only one specific antigen. Monoclonal antibodies are traditionally produced by stimulating the production of B-cells in mice injected with the antigen. These B-cells produce antibodies against the antigen. B-cells can be isolated and made to fuse with immortal tumour cells (so that they can multiply uncontrollably). They can then be cultured indefinitely in a suitable growing medium. Monoclonal antibodies are useful for 3 reasons: They are uniform (i.e. clones), they can be produced in large quantities, they are highly specific
What are antibiotics?
Antibiotics are medications that destroy or slow down the growth of bacteria. They only work against bacteria (not against viruses or fungi) because they target bacterial metabolism specifically. This is also why they have relatively few side effects on humans. Antibiotics are generally divided into two functional categories: Bactericidal which kills bacteria, and bacteriostatic which stops bacteria from dividing, so the immune system has time to destroy them. Bacteriostatic medications may be preferable over bactericidal in some situations, as when some bacteria die they may release harmful toxins.
What is hypersensitivity?
Hypersensitivity refers to an immune system response to an antigen beyond what is considered normal. The immunological response to the antigen (or allergen) leads to tissue damage rather than immunity. Hypersensitivity reactions occur when a person has been sensitized to an antigen. Allergic reactions (e.g. hayfever, asthma, and anaphylaxis from insect venom or drug injections) occur very rapidly. Antibodies respond to an allergen by causing the release of histamine from mast cells.
What is the basis of hypersensitivity?
B cell encounters the allergen and differentiates into numerous plasma cells. The plasma cells produces antibodies. Antibodies bind to specific receptors on the surface of the mast cells. The mast cell binds the allergen when it encounters it again. The mast cell releases histamine and other chemicals, which together cause the symptoms of an allergic reactions.
Describe hayfever.
Hayfever (allergic rhinitis) is an allergic reaction to airborne substances such as: dust, moulds, pollens, and animal fur or feathers. Allergy to wind -borne pollen is the most common. Certain plants (e.g. ragweed and privet) are highly allergenic. There appears to be a genetic susceptibility to hayfever, as it is common in people with a family history of eczema, hives, and/ or asthma. Those with hayfever are best to avoid the allergen, although anti -histamines, decongestants, and steroid nasal sprays will assist in alleviating symptoms.
Describe asthma.
Asthma is a chronic (long term) disease of the lungs. It inflames and narrows the airways, resulting in difficulty breathing. Asthma is a common disease, affecting over 2 million people in Australia. It occurs in people of all ages, but most commonly first appears in childhood.
Asthma is often triggered by an allergy to house dust, pollen, and animal dander (shed skin cells, hair, feathers, etc). Asthma involves the production of histamines. The reaction occurs in the small airways (bronchioles) where the histamine causes constriction, accumulation of fluid and mucus, and inability to breathe. Asthma attacks are often triggered by environmental factors such as cold air, exercise, air pollutants, and viral infections.
What is autoimmunity?
Misdirected immune response that occurs when the immune system goes awry and attacks the body itself. Autoimmunity is evidenced by the presence of autoantibodies (antibodies directed against the person who produced them) and T cells that are reactive with host antigens. Normally, the immune system does not attack self. This is ensured by elimination of auto-reactive lymphocytes during their development (negative selection). However, there is a large group of diseases in which the immune system does attack self- cells: autoimmune diseases. The attack can be either humoral (by auto- antibodies) or cellular (by auto- reactive T cells).
List Autoimmune diseases.
Specific: Juvenile diabetes (attacks insulin-producing cells), Multiple sclerosis (attacks myelin coating of nerve axons), and Myasthenia gravis (attacks nerve- muscle junction)
Systemic: Immune complexes accumulate in many tissues and cause inflammation and damage: Systemic Lupus Erythematosus (anti-nuclear antibodies): harms kidneys, heart, brain, lungs, skin, and Rheumatoid Arthritis (anti-IgG antibodies): joints, hearts, lungs, nervous system
What could cause the immune system to attack the self?
Changes in self -antigens, that make them look like non- self to the immune system, due to: Viral or bacterial infection, Medication, and Pollutants.
Changes in the immune system: Normal auto -antibodies exist; mutations in B cells producing them may create pathogenic auto- antibodies and/or Problems with control of lymphocyte development and differentiation.
