Ontogeny of the Immune System

Question 1

An immature B cell has ____ only, while mature B cells have both _____ and _____.

Answer 1

surface IgM; surface IgM and surface IgD

Question 2

The half life of IgG is _____.

Answer 2

three weeks

Question 3

Hematopoietic stem cells arise from ___________.

Answer 3

endothelial cells in the aorta (that themselves arose from lateral plate mesoderm)

Question 4

A cell with cytoplasmic IgM but no surface IgM is called a ______.

Answer 4

pre-B cell

Question 5

An immature B cell has _______.

Answer 5

sIgM and cIgM

Question 6

A mature B cell has _______.

Answer 6

sIgM and sIgD

Question 7

If an immature B cell (with sIgM but no sIgD) binds to an antigen, then it will undergo _______.

Answer 7

receptor editing; if this fails, then the cell will undergo apoptosis

Question 8

When a B cell sees antigen, it first secretes ______. Helper T cells must induce them to change to other immunoglobulins.

Answer 8

IgM

Question 9

During second exposure, the ______ response is roughly equivalent to the first exposure, but the ____ response is much stronger and faster.

Answer 9

IgM; IgG

Question 10

Prior to birth, fetuses only make _____.

Answer 10

IgM (the rest are not made until 3-6 months after birth)

Question 11

In the thymus, a high concentration of _______ induces lymphocyte precursors to become T cells.

Answer 11

Notch ligands