B-II Adaptive immunity Flashcards
(53 cards)
What is the primary function of B cells in adaptive immunity?
Produce antibodies
B cell response is referred to as humoral immunity.
How are T cells and B cells connected in the immune response?
T-cells and B-cells interact, with T-cells activating B-cells and triggering isotype switching and affinity maturation. B-cells can also act as antigen-presenting cells to activate naive T-cells
What is the role of CD4+ helper T-cells?
Produce cytokines to activate macrophages and stimulate inflammation
CD4+ T-cells require antigen-presenting cells (APCs) for activation.
What does the B-cell receptor (BCR) resemble?
An antibody
BCR is a membrane-bound form of antibody.
What is the importance of IL-7 in lymphocyte development?
It is an important growth factor
IL-7 is crucial for the development and survival of B and T lymphocytes.
What is the function of chemokines in lymphocyte migration?
Attract lymphocytes to specific areas
Chemokines interact with receptors on lymphocytes to guide them to lymph nodes.
What are the components of the T-cell receptor (TCR)?
one α and one β chain
TCR consists of one alpha and one beta chain.
What is the role of the high endothelial venule (HEV) in lymphocyte trafficking?
Allows naïve lymphocytes to migrate into lymph nodes
HEVs have specific ligands that slow down lymphocytes for entry.
What is the structure of an antibody?
2 heavy chains and 2 light chains
Antibodies have a variable region for antigen binding and a constant region.
What is affinity maturation?
Increased affinity to antigen through somatic hypermutations
Affinity maturation occurs in germinal centers when B-cells interact with T-cells.
What is isotype switching in B cells?
Change of antibody type without changing affinity
Triggered by T-cell cytokines, B-cells can switch from IgM to other isotypes.
What are the functions of IgG antibodies?
Bind antigens, activate complement, stimulate ADCC
IgG is the most abundant antibody in humans and plays a key role in immune responses.
True or False: CD8+ T-cells recognize MHC Class II presenting antigens.
False
CD8+ T-cells recognize MHC Class I presenting antigens.
Fill in the blank: The _______ is a secondary lymphoid structure in the gut.
Peyer’s patch
Peyer’s patches are important for gut immunity.
What are some of the functions of antibodies in the immune system?
Neutralization and opsonization of pathogens
Antibodies bind to antigens, making them harmless and marking them for destruction.
What is the difference between affinity and avidity?
Affinity is the strength of binding at a single site, while avidity is the overall strength of binding considering multiple sites
Avidity reflects the total strength of interactions between multivalent antibodies and antigens.
What triggers the activation of CD4+ T-cells?
Presentation of antigen by MHC Class II on APCs
This interaction stabilizes the binding of TCR and MHC Class II.
What is the main role of memory T-cells?
To provide long-lasting immunity
Memory T-cells can quickly respond to previously encountered antigens.
What is the function of the Fc region of an antibody?
Activate complement system and bind to Fc-receptors on immune cells
The Fc region is critical for mediating immune responses.
Which BCR is expressed by naive B-cells?
IgM and IgD
Where does the T and B lymphocyte mature, respectively?
The T-lymphocyte moves to the thymus, while the B-lymphocytes stays in the bone marrow
Name three receptors T-cells need to express to be transported to the lymph nodes?
L-selectin, CCR7, LFA-1
What does L-selectin do?
The ligand is found on the HEV, which allows the T-cells to adhere to the walls and “stop” by the lymph nodes
What does CCR7 do?
Chemokine receptor, recognize chemokines and activates migration to the T-cell zones in lymph nodes. It also activates expression of LFA-1 receptor
