Which antibody class is secreted first in a primary response?
Where do B cells mature?
- In the thymus
- In the bone marrow
- In the spleen only
Each mature B cell clone carries a unique binding site built by gene shuffling.
Circle one: True False
What happens to a developing B cell that grips self strongly in the marrow?
- It is kept as a memory cell
- It is deleted by apoptosis
- It switches to making histamine
Why is the second response to a virus faster and stronger?
- Memory B cells from the first meeting respond at once
- The virus becomes weaker on its own
- Red blood cells start making antibodies
How does a ragweed allergy unfold on second exposure?
- IgM bursts the pollen grains directly
- Helper T cells eat the pollen whole
- IgE on mast cells binds pollen and triggers histamine release
A mature B cell that binds self but gets no helper T cell signal should keep making antibody anyway.
Circle one: True False
A student says autoimmunity and allergy are the same thing: too much immunity. What is the correction?
- One targets self, the other targets a harmless outsider
- Both are caused by weak bone marrow alone
- Neither involves antibodies at all
Endless antibodies, faster second meetings W1-mt_5YXKhiOqoA-s1
- IgM · Plasma cells release IgM early, and strong IgG follows later or on re-exposure.
- In the bone marrow · B cells are generated and mature in the bone marrow, where tolerance starts.
- True · Random segment joins give nearly every clone its own receptor.
- It is deleted by apoptosis · Clonal deletion removes strongly self-reactive cells before they can do harm.
- Memory B cells from the first meeting respond at once · Surviving memory cells skip the slow first steps and pour out better-binding IgG.
- IgE on mast cells binds pollen and triggers histamine release · IgE made at first exposure arms mast cells, which spill histamine when pollen returns.
- False · Missing helper approval marks it for death, which is peripheral tolerance at work.
- One targets self, the other targets a harmless outsider · Each is a specific tolerance failure with a different target, not general excess strength.