Chapter 3 AI generated Flashcards
What is the antigen that a given B cell recognizes called?
The antigen that a given B cell recognizes is called a cognate antigen.
What is the tiny region of an antigen that the B cell receptor (BCR) binds to called?
The tiny region of an antigen that the BCR actually binds to is called the epitope.
How do BCRs send a signal to the nucleus when they find their epitope?
BCRs have two accessory proteins, Iga and Igb, which interact with signaling molecules inside the cell to initiate an enzymatic reaction chain.
Define crosslinking in the context of B cell activation.
Crosslinking refers to the process where many BCRs are brought close together, leading to interactions between Iga and Igb proteins with signaling molecules inside the cell.
What is the function of a complement receptor on the surface of a B cell?
The complement receptor recognizes ‘decorations’ on a pathogen, amplifies the signal when bound to the BCR, and is also known as a co-receptor.
How are naive B cells activated to become experienced B cells?
Naive B cells can be activated through T cell-dependent activation (requiring CD40L-CD40 interaction) or T cell-independent activation (via unambiguous danger signals like TLR activation).
What is the advantage of T cell-independent activation of B cells?
T cell-independent activation is faster as it does not require waiting for Th cells, and it is antigen-specific, activating only B cells whose receptors recognize the repeated epitope.
Describe the importance of the requirement for 2 signals before B cell activation.
Requiring 2 signals helps prevent self-reactive B cells from being activated, ensuring a more specific and controlled immune response.
Describe the structure and function of IgM antibodies.
IgM contains 5 IgG antibodies stuck together, which can activate the classical pathway by bringing together C1 complexes.
What is the role of IgG1 antibodies in the immune system?
IgG1 can opsonize for professional phagocytes, aiding in the process of phagocytosis.
Define the function of IgG3 antibodies.
IgG3 antibodies can fix complement and form bridges for NK cells, facilitating antibody-dependent cellular cytotoxicity (ADCC).
How does IgA contribute to immune defense in the body?
IgA guards mucosal surfaces in the digestive, respiratory, and reproductive tracts, clumping pathogens together for removal from the body.
Describe the unique ability of IgG antibodies in maternal-fetal immunity.
IgG antibodies can pass from the mother’s blood to the fetus via the placenta, providing protection to the baby with a half-life of about 3 weeks.
What is the significance of IgE antibodies in the immune response?
IgE antibodies are involved in allergic reactions and are associated with mast cells, playing a role in allergic responses and inflammation.
