Immunity in the Airway Flashcards
Describe the maturation process of naive B cells in the germinal centres
Subcapsular sinus (SNS) macrophages present whole antigens to naive follicular B cells.
Antigen-specific B cells get activate.
B cell goes through somatic hypermutation (SHM) to express different versions of its antibody in the dark zone
The cells are apoptotic and rely on survival signalling from follicular dendritic cells and Tfh cells.
They present their antibodies to the fDC and Tfh - if low affinity or autoreactive, they go through apoptosis.
If high affinity, they recieve survival signals.
They leave the germinal centre and differentiate into Plasma cell or memory IgM+ and IgG+ cells
What natibody is found in mucosa and how does it get there?
IgA
Transcytosis of IgA: IgA dimer (with J chain) binds to IgA receptor on epithelial cell
Endocytosed into endosome
Exocytosed with secretory component(allows resistance against enzymes)
Diversity in B cells is acheived by gene recombination/somatic hypermaturation. What regulates this process and how does it work?
Needs activation by cytidine deaminase (AID/Aicda)
Mechanism: switches cytosine into thymine (C -> U -> T)
Explain what Tissue Resident Memory is and how it affects immunity
T cells which reside in tissues without recirculating.
Cause an increased response to re-infection
