Antibodies & Antigen Receptors

IgM

What is the most primitive antibody?

IgM

What antibody is short lived and does not have memory?

IgG

What antibody is long lived and has a memory function?

Humoral immune response

Secretion of antibodies

1. Isotype switch

2. High affinity and specificity

3. Memory B cells

What 3 things only occur via T cell dependent activation?

Efferent lymph

Mature B cells travel to the lymph node via the bloodstream and leave via the ___________________

High endothelial venules

Specialized capillary that helps activated lymphocytes get into the peripheral blood from lymph node (also does the opposite)

A

T or F: Both B and T cells after being activated will move to the edge of the follicle for T-B activation

Immunoglobulins

Glycoprotein molecules which are produced by plasma cells in response to an immunogen and which function as antibodies

Antigenic determinant

Each immunoglobulin binds to a specific ___________________

Antigen binding

What is the primary function of antibodies that can result in protection of the host?

Antitoxin

Antibodies against a specific toxin

Normal serum

Describe the serum electrophoresis

Polyclonal gammopathy

Describe the serum electrophoresis

Monoclonal gammopathy

Describe the serum electrophoresis

Polyclonal gammopathies

Characterized by an increased in all immunoglobulins as a result of excessive activity of many different clones of plasma cells

Infections/autoimmune disease

What should you think about for polyclonal gammopathies?

Monoclonal gammopathies

Due to a single precursor of clone plasma cell that secrete homogenous immunoglobulins

Myeloma (plasma cell tumor)

What should you think about for monoclonal gammopathies?

Valency

The number of antigenic determinants that an individual antibody molecule can bind

2

The valency of all antibodies is at least what?

Effector functions

Significant biological effects are a consequence of secondary ______________ of antibodies

1. Neutralization

2. Opsonization

3. Complement activation

4. Antibody dependent cell mediated cytotoxicity

What are the (4) antibody effector functions?

1. V (variable) region

2. C (constant) region

What are the two functional parts of antibodies?

V (variable) region

H & L chains ("Fab") are the antigen binding sites

C (constant) region

Heavy chains ("Fc") determine biological role

Antigen binding site

The V (variable) region has what function?

1. Binding to Fc receptors

2. Complement binding site

3. Placental transfer

The C (constant) region has what function?

Idiotype

The specific combination of idiotopes present within an antibodies complement determining regions (CDRs)

Idiotope

Specific region within an antibodies Fv region which binds to the paratope (antigenic epitope binding site) of a different antibody

5

Mammalian B cells make how many different isotypes of heavy-chain constant regions?

2

Mammalian B cells can make _______ different types of light chain constant regions

2

What is the valency of IgG?

2

What is the valency of IgD?

4

What is the valency of IgA?

2

What is the valency of IgE?

10

What is the valency of IgM?

Cytokines

What causes isotype switching in B cells?

Isotype

The expression of a specific __________ determines the function of an antibody via the specific binding to Fc receptor molecules on different immune effector cells

A

T or F: Isotype expression reflects the maturation stage of a B cell

B (helper T cells)

T or F: Isotype switch consists of a change in the heavy-chain constant region made by B cells, which is directed by signals from other B cells

Late

Isotype switch occurs ________ in a primary immune response

Immunoglobulin allotype

The allele of the antibody chains found in the individual

IgM

What is the biggest antibody isotype?

IgD

Antigen receptor on naive B cells whose function is unknown

B

T or F: IgD binds complement

IgM

B cell receptor on naive B cells

IgM

What is the first isotype produced in the primary immune response?

Blood

IgM acts within what?

Complement

IgM efficiently activates _____________

A

T or F: IgM agglutinates more efficiently than IgG

B

T or F: IgG is more efficient at activating complement than IgM

IgG

What is the most abundant isotype in mammalian serum?

Blood and extravascular fluid (systemic)

Where is IgG located?

A

T or F: Soluble IgM and IgG will not activate complement

Late

Agglutination by IgG is greatest during what phase of the immune response?

Opsonization

IgG is very good at what?

IgA

What antibody isotype is predominant in mucosal secretions?

Microbials and toxins

IgA prevents the attachment of what?

J chain

Dimeric IgA is bound by what?

Secretory molecule

Dimeric IgA binds to what to be able to secreted into the lumen?

Parasites and allergies

IgE is associated with what?

Mast cells

IgE binds to Fc receptors on what?

Constant region (AKA Fc region)

What defines how a specific antibody will contribute to an immune response?

IgM

What is the predominant isotype for the primary antibody response?

IgG

What is the predominant isotype for the secondary antibody response?

Memory B cells

What is importantly made with the primary antibody response?

Secondary

The total immunoglobulins is higher during the (primary or secondary) antibody response?

IgG

What is the dominant immunoglobulin in animals?

T cells

(T cells or B cells) distinguish antigens through the primary amino acid sequence

1. Antigen must be processed by APC

2. Antigen must contain protein or peptide

3. Fragment must be displayed in MHC

What are the requirements for T cells to recognize an antigen?

B cells

(T cells or B cells) distinguish antigens through their 3-dimensional structure

A

T or F: Antigens are not processed for B cells to recognize antigens

B

T or F: The epitope cannot bind directly to the B cell receptor

Paired peptides

T and B cells have what in common?

T cell receptors (TCRs)

_________________ contain alpha and beta chains

B cell receptors (BCRs)

________________ contains 2 H chains and 2 L chains (H + L are paired)

2

B cell receptors have what valency?

1

T cell receptors have what valency?

A

T or F: T cell receptors ends of each peptide have different functions and composition

Heavy and light regions

B cell receptor variable regions contain variable ______________________

3

Each variable region of the antigen binding site has _____ hypervariable sites

Complementarity determining regions (CDR)

Antigenic specificity conferred by three hypervariable loops

Non-covalent

The forces that hold an antigen in the receptor are ______________

A

T or F: Antigen binding is not permanent and can be altered by minor changes in shape and charge

VDJ recombination

the process by which T cells and B cells randomly assemble different gene segments - known as variable (V), diversity (D) and joining (J) genes - in order to generate unique receptors (known as antigen receptors) that can collectively recognize many different types of molecule

In bone marrow

The earliest events of VDJ occur where?

Secondary lymphoid organs

Later steps in B cell development happen where?