The Immune Response Flashcards
Latent Phase (aka: lag or inductive)
After initial exposure to an immunogen it is the period of time before Ab can be detected
Exponential Phase (aka: logarithmic)
Ab begins and rate of production increases resulting in exponential increase in Ab concentration
Steady State
Peak Ab concentration
Decay (aka: decline)
Decline in Abs followed by a time when a small amount of Ab can be detected
Secondary Response (aka: memory)
After initial exposure to Ag
How does 2ndary response compare to primary?
Faster - Shorter lag time Higher rates of Ab synthesis Higher peak of Ab Longer persistent response Predominance of IgG Higher affinity to Ab Requires less Ag
B-cells
Express surface Ig
Each only allowed to express a SINGLE variable region
What is repertoire?
The total population of B-cells make up the repertoire of Ab specificities
How are Ags seen
Seen by B-cells–> and those cells with COMPLEMENTARY Ig sequence will respond
How are T-cells involved in this process?
They aid in BC proliferation
Clonal Expansion
A single BC can produce up to 1000 daughter cells in 10 days
- As immune response continues there is an increase in affinity of Ab produced
- Class switching occurs (IgM–>IgG)
How can increase affinity be explained?
As a selective expansion of those clones w/ the highest affinity to Ag
-As [Ag] drops only those clones w/ the highest affinity will be stimulated
Helper T-cells - CD4+
Recognize diff set of Ags than BCs
Most Ags it reacts to are proteins or peptides
How do TCs react with Ag
React with Ag on the surface of the APC and in response to Ag (with MHC) and co-stimulatory molecules
-TCs proliferate and produce factors that stimulate BCs
How do BCs respond to TCs
- Many daughter BCs will react to TC derived factors and differentiate into plasma cells
- Other TC factors involved in switching IgM production to IgG
- Some of the daughter cells wont differentiate and will become memory cells
