The Immune Resonse Flashcards
What are the phases of antibody production?
1- Lag phase 2-Logarithmic/ exponential rate 3- Steady state 4- Decay/ decline phase 5- Extended period of time when a small amount of antibody can be detected
What is the lag phase?
The amount of time before antibody can be detected. Typically 4-7 days for a primary response.
What Ig is most prevalent during a primary response?
IgM
When is IgG detectable after exposure?
About 2 weeks after the immune response
Compare a secondary immune response to a primary immune response?
Secondary is stronger, faster.
Shorter lag time and higher rates of antibody synthesis, reaching a higher peak of antibody titre.
Requires less antigen to stimulate.
Ig is typically of higher affinity.
Does Ig stay around longer in a primary response or a secondary response?
A secondary response
What type of Ig doe memory B cells make?
IgG
What is an idiotype?
A single variable region expressed on a B cell
What occurs when a B cell finds its matching antigen?
Antigen is presented with T cell help
Clone starts expanding
Daughter cells are produced
What is clonal expansion?
1 B cell can make up to 1000 daughter cells in 10 days. It is an increase in number of B cells that are specific to the antigen
As the immune response, what happens to the affinity of antibodies? Why?
The “affinity” of the antibodies increase because of selective expansion of the B cells that have the highest affinity to the antigen
What antibodies are still made when the antigen concentration drops?
The highest affinity antibodies
What are the surface antigens of Helper T cells?
CD3 and CD4
What is a Hapten-Carrier?
Small molecule attached to a large carrier protein that can illicit an immune response
What is the difference between how T cells and B cells see antigen?
T cels antigens are small sequences of peptide. B cells see conformations
What is needed to activate Helper T cells?
Antigen and MHC, co stimulatory molecules
How do activated Helper T cells activate B cells?
T cells proliferate and then produce factors that activate B cells
How do APCs get antigens?
Endocytosis/ phagocytosis
What enhances activity of APCs?
1- Interaction with compliment
2- Pre-existing antibody
3- specific receptors that recognize pathogens
What happens to an antigen when it is taken up by an APC?
The antigen is digested and a highly immunogenic form of the antigen is created
How are antigen’s presented?
MHC I (CD8+) and MHC II (CD4+)
Who provides the co-stimulatory signals for T lymphocytes?
APCs
What are the 4 requirements of Professional APCs?
1- Take up and process antigen
2- Have MHC class II antigen on its surface
3- Present antigen with MHC class II antigen
4- Provide co-stimulatory signal B7
What is the receptor for B7 on T lymphocytes?
CD28
What are two examples of APCs?
Dendritic Cells and langerhans cells
