Intro to Immunology Flashcards
(28 cards)
What is the immune system
A collection of tissues, organs, cells, mechanical barriers, and chemical substances that protect the body from foreign invaders (antigens).
What are antigens?
Foreign substances that trigger an immune response. Examples: molecules, viruses, blood cells, tumor cells, bacteria, fungi.
What are the two major components of the immune system?
The two major components of the immune system are:
- Innate immunity
- Adaptive (acquired) immunity
What organs are involved in the immune system?
Organs involved in the immune system include:
- Lymph nodes
- Spleen
- Thymus
What are some clinical assays based on immunologic principles?
- Detection of antibodies (e.g., rapid tests for infections)
- Microbial identification (e.g., Widal test)
- Drug and pregnancy tests
Blood and tissue typing (compatibility testing) - Immune function evaluation (CD4 & CD8 testing)
What are the characteristics of innate immunity?
Innate immunity is:
- Inborn (present at birth)
- Nonspecific
- The first line of defense
It includes:
- First line of defense: Mechanical (skin, mucus) & chemical barriers (acids, lysozyme, lactoferrin), normal bacterial flora
- Second line of defense: Phagocytic cells (neutrophils, macrophages), antimicrobial substances, inflammation
What are the characteristics of adaptive immunity?
Adaptive immunity is:
- The third line of defense
- Specific
Characterized by:
a. Recognition – Differentiates between self & non-self
b. Specificity – Binds to specific epitopes
c. Memory – Provides an anamnestic (memory) response
What are the types of phagocytes?
Types of phagocytes include:
- Mononuclear phagocytes: Monocytes (in circulation) and macrophages (in tissues, antigen-presenting cells)
- Polymorphonuclear neutrophils (PMN): Circulate in blood, migrate to tissues, use bactericidal granules
What are the two types of lymphocytes and their roles?
The two types of lymphocytes are:
- B cells – Humoral immunity (antibody production)
- T cells – Cell-mediated immunity (destroy foreign substances)
What is the role of B cells in immunity?
B cells:
- Develop and mature in the bone marrow.
- Produce antigen-specific antibodies through plasma cells.
- Provide lasting immunity through memory cells.
What are the two populations of T cells and their functions?
The two populations of T cells are:
- T helper cells: Recognize and interact with antigens and activate other cells.
- T cytotoxic cells: Involved in antigen processing and presentation.
What are cytokines and their functions?
Cytokines are molecules secreted by cells stimulated by infectious material. They:
- Regulate the intensity and duration of the immune response.
- Provide initiation signals for immune cells.
- Stimulate cells to produce additional cytokines.
What are immunoglobulins (Antibodies)?
Proteins secreted by plasma cells into body fluids that help neutralize antigens.
What are the classifications of immune system diseases?
Immunocompetent: Normal immune response
Immunocompromised: Weak immune system, higher disease risk
Immunosuppression: Reduced immune function (e.g., HIV, treatment effects)
What are some conditions that cause abnormal or diminished immune responses?
Conditions include:
- Malignancies (e.g., leukemia, lymphoma)
- Overactive/misdirected responses (e.g., allergies, autoimmune diseases)
- Inherited immune deficiencies
- Congenital developmental abnormalities
What is the difference between monoclonal and polyclonal antibodies?
Monoclonal antibodies: Derived from one cell line, recognize one epitope.
Polyclonal antibodies: Derived from multiple cell lines, recognize multiple epitopes.
What are the types of immunologic tests?
Immunologic tests include:
- Qualitative tests (positive/negative results)
- Semi-quantitative tests (estimate concentrations)
- Quantitative tests (precisely measure concentrations)
What are some principles of antigen-antibody tests?
Principles include:
- Agglutination
- Precipitation
- Immunofluorescence
- Enzyme immunoassays
- Chromatographic immunoassays
- Flow cytometry
What is agglutination?
Agglutination is the visible clumping or aggregation of cells or particles. IgM is the antibody class that reacts best due to its multivalent binding capacity.
What is radial immunodiffusion used for?
Radial immunodiffusion is used to estimate concentrations of IgG, IgM, and IgA. It forms a visible ring proportional to the sample’s concentration.
What is nephelometry?
Nephelometry is based on the precipitation method, where light is scattered by particles in a sample. The scattered light is measured at an angle to estimate concentrations.
What are enzyme immunoassays (EIA)?
In EIAs:
- Wells are coated with antigen or antibody.
- Samples are added to form an antigen-antibody complex.
- A color substrate specific for the enzyme is added.
- The intensity of the color change indicates the concentration of the target molecule.
What is immunofluorescence?
A technique that uses fluorescent-labeled antibodies to detect specific antigens in cells or tissues under a fluorescence microscope.
Types of Immunofluorescence
- Direct immunofluorescence (DIF): A fluorophore-labeled antibody binds directly to the target antigen.
- Indirect immunofluorescence (IIF): A primary antibody binds to the antigen, and a secondary fluorophore-labeled antibody binds to the primary antibody.
