TUT 2 Flashcards
(21 cards)
How is preparing serum from blood different from isolating plasma from a blood sample?
- Plasma contains vital substances essential for clotting of blood and contains antibodies
- If blood is allowed to clot, a clear straw-colored fluid oozes out. This is SERUM
Serum is plasma WITHOUT clotting factors
What are the four groups of plasma proteins? How were they named?
- Albumin (imp in regulation of water movement between tissues and blood, transports hormones,vit,minerals around the body)
- Gamma-globulins (immune system/transport molecules)
- Fibrinogen (responsible for formation of blood clots)
Whata re the functions of albumin in blood
- Colloid osmotic pressure of blood is 80% due to albumin (low MW and regulates water distribution)
- Transport of FA and calcium/copper/drugs
- Source of aa for tissue cells
General structure of an immunoglobulin molecule.
What is an Fab an F(ab prime) 2 and and Fc?
Fab: Region on antibody that binds to antigens, detect antigens, precipitate antigens and block active sites of toxins
Fab prime 2: Generated by pepsin digestion of whole IgG antibodies to remmove most of the Fc region while leaving intact some of the hinge region
Fc: Tail region of antibody that interacts with cell surface receptors called Fc receptors –> allows antibodies to activate the immune system (macrophages, NK cells, dendritic cells etc)
Fab region: variable region
Fc region: constant region
What are the classes of antibody and where are they found
(Gordon And Michelle Do Everything)
IgG: Found in blood and lymph
IgA: Found in serum and mucous membranes (respiratory passages and GIT)
IgM: Found in all body fluids
IgD: Surface of mature B cells
IgE: Bound to mast cells which are found in connective tissue
Why is the Fc part important?
- Fc receptor is a protein found on the surface of certain cells
- Fc receptors bind to antibodies that are attached to infected cells or invading pathogens
- Their activiity stimulates phagocytic or cytotoxic cells to destroy microbes or infected cells
- Fc region also activates complement systems of the immune response
Why is IgE important? What diseases is it associated with?
>Produced in response to an allergen, antibodies travel to cells (mast cells) to release chemicals causing an allergic reaction
>Asthma, food allergies, RA, helminths
What are hypervariable regions? What is their other name?
Hypervariable regions form the antigen-binding site
- Also called Complementarity-determining region (CDRs)
- Target specific antigens that have the ability to bind to the Fab region
What is a multiple myeloma and what do myeloma cells produce
- Cancer of the plasma cell
- Produce an abnormal type of IG called paraprotein (monoclonal IG)
How many different ways do antibodies specifically protect the body?
3 different ways
- Antibodies neutralize bacterial toxins, viruses and bacterial cells
- Antibodies coat an antigen and render it reccognizable as foreign by phagocytes (macrophages and neutrophils) which ingest and destroy it –> opsonisation
- Antibodies activate the complement system by coating a bacterial cell
Describe steps needed to prepare a monoclonal antibody
- Immunize animal with antigen
- Remove animals spleen
- B cells are fused with myeloma cells resulting in hybridomas
- Hybridomas are screened to find out which antibodies are being produced in response to the antigen
- Each hybridoma cell is derived from one B-cell so the antibodies that are produced are monoclonal antibodies
What is the difference between a polyclonal antibody response and a monoclonal antibody response
- Monoclonal antibodies recognize one epitope only
- Polyclonal antibodies recognize multiple epitopes
Polyclonal antibodies are much less expensive to produces than monoclonal antibodies
Epitopes = Part of antigen that interacts with antibody
What could you use monoclonal antibodies for?
Treatment of disease (asthma, arthritis, cancer, multiple sclerosis)
What are J chains and secretory pieces and where would you find them
J chains needed for multiple forms (dimer) –> Required for IgA and IgM to be secreted into the mucosa
>Found on IgA and IgM
>Small polypeptide
Secretory IgA is formed during transport through mucous mebranes and epithelial cells
Why is a hinge region important on immunoglobulins? Do they all have one? (p639) hinge region= flexible aa
>Region between the domains in the immunoglobulin which can readily be cleaved using pepsin
>Provides flexibility and allows both Fab arms to move independently
>Facilitates binding to antigenic sites
>IgM and IgE have no hinge region
What is the difference between affinity and avidity?
Affinity: Measure of binding strength between binding site on antibody and antigen
Avidity: Affinity of multiple binding sites
IgM has typically low affinity antigen binding sites but there are 10 of the so avidity is high
What is meant by humanizing a moncoclonal antibody
Conversion of a mouse antibody to human antibody
Using Michaelis Menten kinetics (ie Vmax and Km), how would you know if an inhibitor was affecting a reaction by being a competitive inhibitor
Competitive Inhibitor: Increase Km and same Vmax
Non-competitive inhibitor?
Same Km, decrease Vmax
Uncompetitive Inhibitor?
Decrease Km and decrease Vmax
If you were to graph an allosteric inhibitor in action using Michaelis Menton kinetics, how would it look compared to a normal, uninhibited reaction
Enzyme less efficient across broad [S]
> Km value is higher
