BI301 - Biology of the B Lymphocyte

The earliest stages of B-cell differentiation:

A) occur in the embryonic thymus
B) require the presence of antigen
C) involve rearrangement of κ-chain gene segments
D) involve rearrangement of surrogate light-chain gene segments
E) involve rearrangement of heavy-chain gene segments

E) involve rearrangement of heavy-chain gene segments

Which of the following is expressed on the surface of the mature B lymphocyte?

A) CD40
B) MHC class II molecules
C) CD32
D) IgM and IgD
E) all of the above

E) all of the above

Which of the following statements is incorrect?

A) Antibodies in a secondary immune response generally have a higher affinity for antigen than antibodies formed in a primary response.
B) Somatic hypermutation of variable-region genes may contribute to changes in antibody affinity observed during secondary responses.
C) Synthesis of antibody in a primary response to a thymus-dependent antigen occurs predominantly in the blood.
D) Isotype switching occurs in the presence of antigen.
E) Predominantly IgM antibody is produced in the primary response.

C) Synthesis of antibody in a primary response to a thymus-dependent antigen occurs predominantly in the blood.

Immature B lymphocytes:

A) have rearranged only D and J gene segments
B) are progenitors of T as well as B lymphocytes
C) express both IgM and IgD on their surfaces
D) are at a stage of development where contact with antigen may lead to receptor editing and deletion
E) must go through the thymus to mature

D) are at a stage of development where contact with antigen may lead to receptor editing and deletion

Antigen binding to the B-cell receptor:

A) transduces a signal through the antigen-binding chains
B) invariably leads to B-cell activation
C) transduces a signal through the Igα and Igβ molecules
D) results in macrophage activation
E) leads to cytokine synthesis, which activates T cells

C) transduces a signal through the Igα and Igβ molecules

Which of the following would not be found on a memory B cell?

A) Igα and Igβ
B) γ heavy chains
C) ε heavy chains
D) surrogate light chains
E) κ light chains

D) surrogate light chains

Germinal centers found in lymph nodes and spleen:

A) support the development of immature B and T cells
B) function in the removal of damaged erythrocytes from the circulation
C) act as the major source of stem cells and thus help to maintain hematopoiesis
D) are sites where antigen-activated mature B cells proliferate and differentiate
E) exclude T cells

D) are sites where antigen-activated mature B cells proliferate and differentiate