Ch 17: Adaptive Immunity Flashcards
Who determined that the body produces excess antitoxins, which turned out to be antibodies, that last beyond an initial exposure?
Paul Ehrlich
Which form of globulins are also known as immunoglobulins?
Gamma-globulin
What is the difference between an antigen and an epitope?
- Antigen: a substance that causes the body to produce specific antibodies or sensitized T-cells
- Epitope: small sections of an antigen that an antibody interacts with
What is a hapten?
An antigen too small to be recognized by the immune system that can be recognized when combined with a carrier protein
What causes penicillin to become immunogenic?
- Binds to a carrier molecule like albumin
- Creates Hapten-carrier conjugate that can be recognized by the immune system
____ accidentally innoculated chickens with month-old cholera. This made them only slightly ill, but made them immune to cholera.
Louis Pasteur
___ discovered that bacterial toxins generated the production of “antitoxins” in serum. He generated antitoxin sera mixed with sera to prevent diphtheria in children.
Emil Von Behring
____ showed that antigens of pneumococcus are polysaccharides and that antibodies are proteins. Aka the “Father of Modern Immunology.”
Michael Heidelberger
___ discovered the general structure of antibodies?
Gerald Edelman
____ worked out how genes in B-cells produce the many different antibodies to virtually any antigen.
Susumu Tonegawa
Define serology
Study of reactions between antibodies and antigens
What cell type makes antibodies?
Memory B-cells
How does the immune system generate a massive diversity of antibodies with only a small handful of genes?
- Segments of genets get recombined to form the variable region
Label the following:
Hinge region, Light Chain, Heavy Chain, Fc region, Antigen-Binding region
What are the 5 classes of Ig?
- IgG
- IgA
- IgM
- IgE
- IgD
Identify the Ig class:
- 80% of serum Abs
- Fix complement
- In blood, lymph, intestines, and can cross placenta
- Enhance pahgocytosis; neutralize toxins and viruses; protect fetus and newborn
- Half-life = 23 days
IgG
Identify the Ig class:
- 5-10% of serum Abs
- Fix complement
- In blood, lymph, and on B cells
- Agglutinates (forms network) with microbes; first Abs produced in response to infection
- Half-life = 5 days
IgM
Identify the Ig class:
- 10-15% of serum Abs
- In secretions (ex: mucus, sebum, etc)
- Mucosal protection
- Half-life = 6 days
IgA
Identify the Ig class:
- 0.2% of serum Abs
- In blood, lymph, and on B cells
- Half-life = 3 days
IgD
Identify the Ig class:
- 0.002% of serum abs
- On mast cells, basophils, and in blood
- Important in allergic reactions and lysis of parasitic words
- Half-life = 2 days
IgE
True or false. A single B-cell can only produce one class of Ig.
False. Over time and as antigen contact decreases, B-cells switch from secreting IgM to IgG
Define agglutination
Clumping of antibody-antigen complexes, reducing the number of infectious units
Define opsonization
- Coating of antigen with antibody to enhance phagocytosis
- Aided by Fc region of an Ig
Where does T cell maturation occur?
Thymus
In order for T cells to be activated, they require interaction with ______
antigen-presenting cells
What cells commonly act as antigen-presenting cells (APCs)? (3)
- B cells
- Dendritic cells
- Macrophages
What is the difference between MHCI and MCHII?
- MCHI → On all cells
- MCHII → Only on immune cells
What are the 3 types of T cells?
- Helper T cells (CD4+ or TH)
- Cytotoxic T cells (CD8+)
- Regulatory T cells (TReg)
How do helper T cells activate B cells?
- T-cell receptors (TCRs) recognize antigens with MHCII on APCs
- B-cells produce antibodies
What is the function of TH1 cells?
- Produce IFN-gamma
- Effective against intracellular pathogens
What is the function of TH2 cells?
Activate eosinophils and B cells to produce IgE
What is the function of TH17 cells?
- Produce large amounts of cytokine IL17
- Recruit neutrophils
- Work against certain extracellular bacteria and fungi
What are M cells?
Facilitate contact between antigens passing through the intestinal tract and cells of the body’s immune system
What is the function of CD8+ T cells?
- Targets infected cells to trigger apoptosis
- “self” antigen
TReg cells have ____ and ____ on their surfaces
CD4 and CD25
What is the function of TReg cells?
SUppress T cells that act against “self” antigens
What are natural killer (NK) cells?
- Extracellular killing by the immune system
- Destroy any cells that don’t express MHCI
- Kill virus-infected cells, tumor cells, and parasites
- Not B nor T
What is the function of cytokine IL-1? (2)
- Stimulate CD4+ cells in presence of antigens
- Attracts phagocytes
What is the function of cytokine IL-2? (3)
- Proliferation of antigen-stimulated CD4 T helper cells
- Proliferation and differentiation of B cells
- Activation of CD8 T cells and NK cells
What is the function of cytokine IL-12? (2)
- Inhibits humoral immunity
- Activates TH1 cellular immunity
What are the four types of adaptive immunity?
- Naturally acquired active immunity → from infection; individual immune response
- Naturally acquired passive immunity → transplacental or via colostrum
- Artificially acquired active immunity → Injection of antigen (vaccination)
- Artificially acquired passive immunity → injection of antibodies
