4 Major characteristics of the adaptive immune system Flashcards
(Characteristic 1: Proliferation of B and T cells)
In the body, a large number of antigen receptors are specific for a given epitope
True or False
False
Only a tiny fraction binds
What happens in the lymph nodes?
an antigen is exposed to a steady stream of lymphocytes until a match is made.
What happens if there is a successful match between an antigen receptor and an epitope?
events that activate the lymphocyte is initiated
Clonal selection
When an activated B or T cell undergoes multiple cell divisions to produce a clone of identical cells
Effector cells
- short-lived cells
-act immediately against the antigen
Plasma cells
- Occur only in B cells
- secretes antibodies
Memory cells
- Long-lived cells
-give rise to effector cells if the same antigen is encountered again
What is responsible for long-term protection against diseases?
Immunological memory
(second characteristic of adaptive immunity)
Primary immune response
The first exposure to a specific antigen.
B and T cells give rise to effector forms during this time
Secondary immune response
when memory cells facilitate faster, stronger, and longer responses
to the same antigen.
(Can span decades)
B and T lymphocytes can produce a humoral immune response and a cell-mediated immune response
True or false
True
Humoral immune response are ___ that help_____or eliminate _____ and ____ in the_____ or ____
antibodies help neutralize or
-toxins and pathogens in the blood or lymph
Cell-mediated immune response is when specialized ____destroy infected ___
T cell
-host cells
Helper T cells
Triggers both the humoral and cell-mediated immune responses
What produces the humoral and cell-mediated responses?
- A foreign molecule must be bound by the antigen receptor of a helper T cell
- An antigen must be displayed on the surface of an antigen-presenting cell
Antigen-presenting cells have class 1 and class 2 MHC molecules
True or false
True
what does the accessory protein called CD4 on the helper T cell do?
It binds the class 2 MHC molecule and this helps keep the cells together/joined
When the helper T cell is activated and proliferates it
forms a clone of helper T cells, which then activate appropriate B cells
Humoral response is characterized by the secretion of ____ through
-Antibodies
-clonally selected B cells
Activation of B cells involves helper T cells and proteins on the surface of pathogens
TRUE or FALSE
TRUE
A single activated B cell give rise to few identical plasma cells
TRUE or False
False
It give rise to thousands
Antibodies do not kill pathogens, instead they mark pathogens for destruction TRUE or False
TRUE
In neutralization, antibodies bind to viral surface proteins but it doesn’t prevent the infection of a host cell
TRUE or FALSE
FAlSE
It does provide infection
Antibodies may also bind to toxins in body fluids and prevent them from entering body cells
True or false
True
Antigen-antibody complexes may bind to a complement protein
True or false
True
A cascade of subsequent events leads to the formation of a pore in the membrane of the foreign cell, leading to lysis
True or false
True
B cells can express 5 different forms or classes of Ig but with different antigen-binding
True or false
False. They have the same antigen-binding
One type of B cell antigen receptor is membrane bound
True or false
True
Some B cell antigen receptors are soluble and found in saliva, tears, blood, and breast milk.
True or false
True
