Lecture 9- Antibodies and Soluble Antigen Receptors Flashcards
What is the role of membrane-bound antibodies?
Act as receptors on the surface of B cells to trigger differentiation into Plasma cells
What is the function of secreted antibodies?
Neutralize microbes and toxins
Three functions of antibodies
Block antigen binding, inhibit spread of infection, and inhibit toxins
Which tube is used to collect antibodies?
Red top
What is the Fab portion of an antibody?
Fragment-antibody binding (antigen binding site)
What is the Fc prortion of an antibody
Fragment crystallizable (Complement activation and binds to cell surface receptors)
What region is found on an antibody between the Fc and Fab regions?
Hinge region
What are the two types of light chain?
Kappa or lambda
Are heavy chains or light chains more important?
Heavy chains
5 different types of heavy chains
α, γ, δ, ε, and µ
What do the different types of heavy chain determine?
isotypes/immunoglobulin class
What immunoglobulin is found in the highest serum concentration?
IgG
What are characteristics of IgG
Strong secondary immune response
Cross placenta
Activates classical pathway
Which immunoglobulin looks like a classic Ig?
IgG, IgD, and IgE
Which immunoglobulin binds to multiple antibodies to form a large ring?
IgM
Which immunoglobulin is found in the second highest serum concentration?
IgM
What are the characteristics of IgM
Primary immune response
Agglutination and complement fixation
Too large to enter tissues
Which immunoglobulin is made of two subunits attached by a J chain
IgA
Which immunoglobulin primarily protects mucosal surfaces?
IgA
Does IgA activate the classical pathway?
No
Which immunoglobulin is found in the serum in small amounts and is associated with worms and allergies?
IgE
Which receptors is IgE known for binding to?
FceR1 on mast cells and basophils
How do allergens stimulate the production of histamines?
By crosslinking IgE and mast cells
Why are allergic responses stronger on the second exposure?
IgE is produced AFTER the first exposure
Which immunoglobulin primarily remains attached to B cells, not circulating in the blood?
IgD
Which cells does IgD bind to?
Basophils
Affinity vs Avidity
Affinity is the strength of binding between an antigen and epitope
Avidity is the overall strength of attachment
What differentiates Ig subclasses?
Hinge region
What is different between allotypes?
Heavy chain
What is different between idiotypes?
Antigen binding sites
What are bovine Igs known for?
long variable domain, ball and stalk structure
What are camelid Igs known for?
Sometimes they do not have a light chain, long hinge region
How many molecules are required for IgG activation of the classical pathway?
Two
Which IL is IgD responsible for producing with basophils?
IL-1 and IL-4
