3- Principles of Adaptive Immunity Flashcards
What is the main difference between innate and adaptive immunity?
Innate is non-specific with no memory, and adaptive is slow and creates a memory using B and T cells.
What is an antigen (Ag)?
A particle that has a specific sequence to which an immunoglobulin or T-cell receptor can bind to.
What is an antigen receptor?
Receptors that bind antigens. They are either immunoglobulins or T-cell receptors.
What are B cell receptors?
Immunoglobulins on the outside of the B cell to which bind matching antigens.
What are T cell receptors?
Receptors on the surface of T cells which bind to specific antigens.
Which region of the immunoglobulin (Ig) molecule binds the antigen?
The variable region- there is a different sequence for each Ig
Which gene segments code the variable regions of the heavy and beta chain?
V, D and J
Which gene segments code the variable region of the light and alpha chain?
V and J
What is the purpose of the V, D and J segments?
They create the diversity in the Ag receptor binding site!
What is clonal selection?
Multiplying the specific lymphocytes for a pathogen so that we can have an effective defense for that pathogen in the future.
Which cells carry the antigen to the naive T cells to bind to the TCR?
Dendritic cells
How are pathogen Ag’s delivered to the lymph node for the adaptive immune response?
Dendritic cells carry the Ag’s on MHC-II’s to the lymph node and wait for the corresponding T cell.
What are the Major Histocompatibility Complexes (MHC)?
They are molecules in every nucleated cell that present antigens to T cells.
Which class of MHC recognizes intracellular pathogens?
MHC-I
Which class of MHC recognizes extracellular pathogens?
MHC-II
What type of T cell corresponds to MHC-I’s?
CD8 Tc cells
What type of T cells correspond to the MHC-II’s?
CD4 Th cells
What cells have MHC-I molecules?
All nucleated cells. Basically everything except RBC’s (don’t have a nucleus).
What cells have MHC-II molecules?
Professional antigen-presenting cells (APC’s_. These are dendritic cells, macrophages and B cells.
What are the 5 Ig molecules?
IgA, IgD, IgE, IgG, and IgM. (GAMED)
Which 2 Ig’s are on the B cell surface?
IgD and IgM
What is the first antibody (Ab) to be secreted in an immune response?
IgM
What are the 3 Ab’s that float around in the blood/lymph?
IgM, IgA and IgG
What is neutralization?
It’s when Ab’s bind tightly to an important site on a pathogen and stop its ability to grow and infect.
Which Ab acts as an opsonin?
IgG
What is somatic hypermutation?
It’s when nucleotide substitution in the variable regions of IgM happen to bind the pathogen more tightly.
What happens after the primary immune response with a pathogen?
Memory cells are created
Since memory cells are created after a primary infection, what happens during the secondary infection?
The pathogen is recognized and killed quickly.
