What are the two types of immunity?
Non-specific (natural, innate) immunity
- can’t distinguish between pathogens
- causes fever (quick) but no memory
Specific (acquired, adaptive) immunity
- different isn’t pathogen by antigens
- specific response for each pathogen (takes longer)
What are the key features of non-specific immunity?
- Skin: mechanical barrier, acid pH, and temp reg.
- Mucous membrane: cilia, lysosomes, and pH reg
- Iron-binding proteins (transferrin)
- Phagocytosis by WBC and macrophages
What is humoral immunity?
- involves circulating antibodies in body fluids to attack specific pathogens
- antibodies are produced by B-lymphocytes in response to antigens
- Antibody production is regulated by T-helper and T-suppressor cells
What is the role of B-lymphocytes in humoral immunity?
- B-lymphocytes produce antibodies
- they require antigen-presenting cells for activation
- T-helper cells help regulate antibody production
What is an antibody (Ab) and it’s function, what is it produced by and what are the 5 types?
An immunoglobulin produced in response to an antigen
- can distinguish foreign macromolecules from body cells
- Produced by B-cells (plasma cells)
- Includes five types: IgG, IgA, IgM, IgE, IgD
What is an antigen (Ag), what does it stimulate, what can it be made of and what does it have?
A substance recognized as “non-self” by the body
- Stimulates antibody production
- Can be a protein, glycoprotein, lipoprotein, or polysaccharide
- Bacterial cells have antigens like capsules, flagella, and cell walls
What are the properties of IgG?
- main antibody in immune response
- can cross the placenta to protect the newborn
- has 2 combining sites for antigen attachment
- binds phagocytes and macrophages for destruction
What are the properties of IgM?
- Made of five units joined together
- First immune globulin produced in early immune responses
- Does not cross the placenta
What is the primary immune response?
- Occurs when an antigen is introduced for the first time
- Delayed antibody production (5-10 days), peaks at 3 weeks, then drops
- Initial response shows a lag period
What is the secondary immune response?
- Occurs when the antigen is reintroduced
- Faster antibody production (2-3 days) with a longer-lasting peak
- Basis for booster injections and immunization
What is the serological reaction?
- Detects antibodies in a serum sample
- Quantifies antibody levels through titration
- Can identify unknown microorganisms with known antisera
What is cell-mediated immunity (CMI)?
- Involves T-cell subpopulations without antibodies
- Active against intracellular organisms (e.g., viruses, parasites)
- Important in defense against tumor cells and foreign cells (e.g., transplants)
What are Antigen Presenting Cells (APCs)?
- Immune cells that display antigens to trigger immune responses
- Drive humoral or cell-mediated immunity, depending on the antigen type
How does the immune system vary?
- It can be affected by factors such as age, race, stress, and nutritional status
- These factors can influence the strength and effectiveness of the immune response
What happens in allergic and hypersensitivity reaction?
- overreaction to antigens without infection
- can lead to anaphylaxis
What are the four harmful effects of the immune response?
- Allergy and hypersensitivity
- Auto-immune diseases
- Immunodeficiency states
- Graft rejection
What are auto-immune disease?
- the immune system attacks the body’s own tissue
- formation of auto-antibodies that target self-materials
What are immunodeficiency states?
- Lack of ability to produce antibodies or cell-mediated immunity
- Can result from congenital issues, irradiation, or diseases like AIDS
What is graft rejection?
- The immune system recognizes transplanted organs (e.g., kidney, heart) as foreign and rejects them
- Requires immunosuppressive drugs to prevent harm to the patient
What is passive immunization and what are the risks?
- Administration of preformed antibodies (IgG) against a pathogen
- Immediate protection but short-lived (lasts about 10 days for animal-derived IgG)
- Risks: hypersensitivity reactions (serum sickness, anaphylaxis)
What is the difference between human and animal-derived IgG in passive immunization?
- Animal-derived IgG: foreign to the immune system, carries risk of hypersensitivity
- Human-derived IgG: shorter-lasting, but no risk of hypersensitivity
What is active immunization?
- Stimulating the body’s immune system by administering a vaccine (antigen or immunogen)
- Longer-lasting protection compared to passive immunization
- produces memory cell
Active immunization - What are live attenuated vaccines?
- Modified viruses that cause mild illness to stimulate immunity
- Provide both local (IgA) and humoral (IgG) immunity
- Can cause serious disease in immunocompromised individuals
Active immunization - What are killed vaccines, subunit vaccines, and toxoids?
- Non-infective vaccines requiring multiple injections for effective immunity
- Toxoids (e.g., tetanus) are administered with adjuvants to enhance immunity
