Antibody Responses in Lymphoid Tissues

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What is the main function of antibodies in the immune system?

To neutralize and eliminate infectious microbes and microbial toxins.

What is the significance of the third hypervariable region (CDR3) in antibody-antigen recognition?

It is the most extensive contact with the antigen and the most variable of the three CDRs.

How is the strength of binding between an antibody and an antigen represented?

By a dissociation constant (Kd).

What term is used to describe the overall strength of attachment of an antibody to an antigen?

Avidity. Signup and view all the answers

Where do class-switched, high-affinity antibody-secreting plasma cells migrate to after being produced in germinal centers?

Bone marrow. Signup and view all the answers

What range does the dissociation constant (Kd) of antibodies typically vary in humoral immune responses?

From about 10^-7 M to 10^-11 M. Signup and view all the answers

What is the role of TFH cells in the development of antibody responses?

TFH cells direct antibody responses in lymphoid tissues. Signup and view all the answers

How are antigens retained for long periods in lymphoid tissues?

Antigens are retained in complexes known as iccosomes. Signup and view all the answers

What process occurs in the germinal center that leads to the production of high-affinity antibodies?

Activated B cells undergo rounds of mutation and selection in the germinal center. Signup and view all the answers

How do high-affinity IgG and IgA antibodies contribute to immunity?

High-affinity IgG and IgA antibodies can neutralize bacterial toxins and inhibit virus infectivity. Signup and view all the answers

What is the half-life of circulating IgM in the bloodstream?

Circulating IgM has a half-life of about 4 days. Signup and view all the answers

What type of cells capture and preserve opsonised antigens in the lymphoid tissues?

Subcapsular macrophages capture and preserve opsonised antigens. Signup and view all the answers

What is the role of the J chain in IgM produced by lamina propria plasma cells?

The J chain is covalently associated with IgM, forming a pentamer. Signup and view all the answers

Where does the poly-Ig receptor transport IgM?

The poly-Ig receptor transports IgM into intestinal secretions. Signup and view all the answers

What initiates the classical complement pathway?

The binding of complement protein C1 to IgG or IgM molecules bound to antigen initiates the classical complement pathway. Signup and view all the answers

Which IgG subclasses are more efficient activators of complement?

IgG3 and IgG1 (in humans) are more efficient activators of complement than other subclasses. Signup and view all the answers

What is the function of opsonization in the immune system?

Opsonization is the process of coating microbes to promote phagocytosis by phagocytes. Signup and view all the answers

Where is the dominance of IgA production by intestinal plasma cells attributed?

The dominance of IgA production is attributed to selective induction of IgA isotype switching in B cells in GALT and mesenteric lymph nodes. Signup and view all the answers