6. B cells I Flashcards
(16 cards)
What is the primary function of B cells?
To produce antibodies
B cells are a critical component of the humoral arm of adaptive immunity.
Where do B cells develop?
In the bone marrow
The ‘B’ in B cells stands for ‘bone marrow’.
How do B cells differ from T cells in terms of antigen recognition?
B cells are not MHC-restricted and can recognize free antigens
T cells require antigens to be presented by MHC molecules.
What do B cells release instead of requiring direct cell contact?
Secreted proteins (antibodies)
This distinguishes them from T cells, which require cell-to-cell interaction.
What is the significance of B cells in patients with impaired function?
They demonstrate critical roles in immunity and long-term protection
Examples include Hyper-IgM syndrome and outcomes after rituximab treatment.
What is the structure of a B cell receptor (BCR)?
A membrane-bound antibody composed of four chains:
* Two heavy chains
* Two light chains
Each chain has variable and constant regions.
What are the five main classes of antibodies?
IgM, IgD, IgG, IgA, IgE
Each class serves different functions in the immune response.
What is the first antibody produced by naive B cells?
IgM
IgM is essential for the initial immune response.
What occurs during the negative selection phase of B cell development?
B cells that strongly recognize self-antigens undergo:
* Deletion (apoptosis)
* Receptor editing
* Anergy
Only about 1/3 of self-reactive B cells are eliminated.
What triggers the transition from Immature to Mature B cells?
Exit from bone marrow to secondary lymphoid tissues
This process includes gaining IgD expression alongside IgM.
What mechanisms generate B cell receptor diversity?
Combinatorial and junctional diversity
This allows for a vast array of different antibodies.
What is the approximate potential for different antibodies in an individual?
5×10¹³ different antibodies
Each person has around 10 billion different antibodies.
How do B cells and T cells differ in their development locations?
B cells develop in bone marrow; T cells develop in thymus
This is a fundamental difference in their maturation processes.
What is the fate of mature naive B cells upon antigen recognition?
They can differentiate into:
* Plasma cells
* Memory B cells
Plasma cells are short-lived antibody factories, while memory B cells provide long-term immunity.
Fill in the blank: B cells can change antibody class through _______.
class switching
This allows B cells to adapt their response to different challenges.
True or False: T cells can rearrange their receptors if they are self-reactive.
False
Unlike B cells, T cells cannot undergo receptor editing.
