C16 Flashcards
is the scientific study of the immune system
and immune responses.
Immunology
Cells involved in immune responses originate in
Bone marrow
three lines of lymphocytes are derived from
lymphoid stem cells of bone marrow:
1. B lymphocytes (B
cells),
2. T lymphocytes (T cells),
3. natural killer cells (NK
cells).
There are two categories of T cells
Helper T cells and cytotoxic T cells
where special glycoproteins called antibodies are produced by B cells to destroy specific microbes
Humoral immunity
involves a variety of cell types, with antibodies playing only a minor role, if any
Cell mediated immunity
- Antibodies are produced within the person
- Usually provides long-lasting protection
Active acquired immunity
immunity that results from the
active production or receipt of antibodies during one’s lifetime
Acquired Immunity
is defined as material that can artificially
induce immunity to an infectious disease, usually following injection or ingestion of the vaccine.
Vaccine
- Antibodies are received that were produced by another person(s) or by an animal
- Usually provides only temporary protection
Passive acquired immunity
Types of available vaccines:
– Attenuated vaccines
– Inactivated vaccines
– Subunit vaccines
– Conjugate vaccines
– Toxoid vaccines
Vaccines stimulate the recipient’s immune system to produce
Protective antibodies
Small antibodies, IgG, present in mother’s blood cross the placenta to reach the fetus
Natural passive acquired immunity
Antibodies from an immune person are transferred to a susceptible person (e.g., hepatitis B immunoglobulin).
Artificial passive acquired immunity
The increased production of antibodies following the second exposure to a particular antigen is called the
Secondary response
Foreign organic substances that are large enough to stimulate the production of antibodies
– Substances capable of stimulating antibodies are said to be antigenic (or immunogenic).
– A bacterial cell has many molecules (antigenic determinants) on its surface that are capable of stimulating the production of antibodies.
Antigens
Where do immune responses occur?
initiated in the spleen; responses to microbes
and other antigens in tissues are generated in lymph nodes located near the infected area.
Proteins produced by lymphocytes in response to the presence of an
antigen
Antibodies
The initial immune response to an antigen is called the primary response; it takes
10 to 14 days for
antibodies to be produced.
Long-lived, antibody-producing cells called, are produced by combining a single plasma cell and a rapidly dividing tumor cell.
Hydbridomas
Hybridomas are capable of producing large amounts of specific antibodies called
monoclonal antibodies.
Monoclonal antibodies are used in
immunodiagnostic procedures (i.e., immunologic procedures used in laboratories to diagnose diseases).
Antigen–antibody complexes are capable of activating the complement cascade, which results in some of the following effects:
– Activation of leukocytes
– Lysis of bacterial cells
– Increased phagocytosis as a result of opsonization
Cell-mediated immunity (CMI)
macrophages, TH cells, TC cells, NK cells, and
granulocytes
A complex system of interactions among many types of cells and cellular secretions (cytokines)
Cell-mediated immunity (CMI)
refers to an overly sensitive immune
system.
Hypersensivity
are a subpopulation of lymphocytes called
large granular lymphocytes.
NK (Natural Killer) Cells
Different types of hypersensitivity reactions
Immediate type: occurs within few minutes
Delayed type: occur in 24hrs, Also known as type IV hypersensitivity reactions.
Type I immediate hypersensitivity is probably the most common type of hypersensitivity.
The Allergic Response
– Results from the release of chemical mediators from basophils in the bloodstream
– Occurs throughout the body—much more serious than localized anaphylaxis
– Common allergens involved are drugs and insect venom
Systemic anaphylaxis
Latex can trigger any of three types of reactions: irritant contact dermatitis, allergic contact dermatitis, or immediate type hypersensitivity.
Latex allergy
Type II hypersensitivity reactions,meaning that body cells are destroyed during
these reactions
Cytotoxic reactions
Sequence of events in a type II hypersensitivity reaction:
- A particular drug binds to the surface of a cell.
- Antidrug antibodies then bind to the drug.
- Complement activation on the cell surface is initiated.
- The complement cascade leads to lysis of the cell.
Type III hypersensitivity reactions are, reactions—such as those that occur in serum sickness and certain autoimmune diseases (e.g., systemic lupus erythematosus and rheumatoid arthritis).
Immune complex
result when a person’s immune
system no longer recognizes certain body tissues as “self” and attempts to destroy those tissues as if they were “nonself” or foreign.
Autoimmune diseases
Persons whose immune systems are not functioning properly are said to be
immunosuppressed.
help diagnose infectious diseases by detecting either antigens or antibodies in clinical specimens; test results are usually
available on the same day!
Immunodiagnostic procedures (IDPs)
– Performed in vivo
– Antigens are injected within or beneath the skin.
– Example: the TB skin test
Skin Testing
