B-Cell Immunity - Shlomchik Flashcards
Where are B and T-cells located during the initiation of an adaptive response?
In microanatomical locations such as B-cell follicles and T-cell zones in the spleen.
What directs the chemotaxis of lymphocytes during the initiation of an adaptive response?
Activated lymphocytes will alter gene expression of chemokine receptors. Chemokine gradients directs cells to specific locations.
Where do T and B-cells first interact in the spleen?
The T-B-cell border, then at the T-zone, red pulp border. Some activated lymphocytes will then migrate back to the follicle and proliferate to form a germinal center.
Which txn factor is required for germinal center formation?
BCL6
How often do Germinal Center B-cells divide?
Every 6-8 hours.
What does activation-induced cytidine deaminase (AID) do? What does it result in?
AID introduces point mutations in the
What is the predominant mode of response to T-independent antigens, some bacterial antigens, and several autoantigens? Does not lead to germinal center formation.
The plasmablast extrafollicular response.
Example of a pathogen that does not cause a germinal center response
Salmonella
Describe the definition of memory B-cells
Antigen experienced, present at increased frequency in a resting state for many weeks/months, and responds to secondary stimuli.
Surface Marker of Human memory B-cells
CD27
Describe Plasma cells
Antibody secreting cells which are terminally differentiated.
What are the two types of plasma cells?
Short-lived, proliferating plasmablasts and long-lived, non-proliferating plasma cells.
Key txn factors of plasma cells
Blimp-1, IRF4, and XBP-1
When do memory B-cells and plasma cells form during a response?
Memory cells are made early in the response, and plasma cells made late.
B-cell intrinsic factors that differ from immune animal to non-immune animal.
- Higher number of antigen-specific B-cells
- Higher affinity BCR
- Different signaling and transcriptional networks
- Much longer in vivo half-life
