normal lymphopoiesis Flashcards
lymphocytes evolve from….
pluripotent stem cells
B lymphocyte do what?
- humoral immune system
- make antibodies
two types of T cells
- cytotoxic
- helper/suppressor
what do cytotoxic T cells do?
- direct killing
what do helper/suppressor T cells do?
- fine tuning via cell-cell interaction and secretion of cytokines
what are the primary lymphoid tissues and what is found there?
- bone marrow - B cells
- thymus - T cells
what are the secondary lymphoid tissues and what is found there?
- lymph nodes
- spleen
- MALT (mucosal associated lymphoid tissue) lining respiratory and GI tracts
- antigen driven differentiation and replication into committed effector cells
explain lymphoid variation
in the cortex of the lymph node, primary lymphoid follicles can change to secondary lymphoid follicles with germinal centers under immune stimulation
in what part of the lymph node do B cells reside?
primary and secondary follicles of the cortex
in what part of the lymph node to T cells reside
paracortex
in what part of the lymph node do plasma cells reside?
medulla, release immunoglobulins into the efferent limb
what are the three parts of the splenic follicle from outside to inside?
marginal zone
mantle zone
germinal center
what B cell stages of development happen in the bone marrow?
pluripotent stem cell -> B cell progenitor -> pro B cell -> pre B cell
what B cell stages happen in the peripheral blood/secondary lymph tissues?
naive mature B cell -> antigen activated B cell -> plasma/memory cells
what is the ratio of B cell light chain proteins
2:1, kappa:lambda
when is a B cell mature?
in bone marrow once it can express IgM and IgD along with the B cell receptor complex
surface antigens in early B cell development
CD79 Bruton tyrosine kinase CD10 CD20 CD22 TdT
what happens to mature B cells in the germinal center?
somatic hypermutation (SHM) - an error prone proliferation ending in high affinity antibody producing B cells
class switching
what antigens are expressed by plasma cells
CD38+ and CD138+
what happens to activated B cells that do not interact with T cells?
become short-lived plasma cells and secrete IgM
what does a memory cell do and how long does it live
- makes specific plasma cells faster than simply an activated B cell
- years to decades
percentages of T cell receptors (TCRs) in T cells
- > 95% have alpha/beta TCR (TCR2)
- rest have gamma/delta TCR (TCR1)
cytotoxic T cells express…
CD8
helper T cells express….
CD4
