IMM2022 Study Guide - Final Guide: Flow Cytometry, Cd19, B-Cell Linker
4 May 2018
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IMM2022: Immunodeficiency summary
notes
FLOW CYTOMETRY
Forward scatter: size (X axis)
Side scatter: complexity (Y axis)
Markers
• CD3 = TCR complex (Tcell)
• CD19 = dev to mature B cells (not on
plasma cells)
• CD20 = B cells (pro increases with
maturity)
• CD16 on NKC
Note that on a normal mature B cell you will
find CD19 and CD20
Case study 1
Sepsis is the presence and proliferation of
bacteria in the blood
Agammaglobulinemia is an inherited disorder
– low levels of immunoglobulins (Increased
risk of infection)
In blood albumin is the major protein. Looking
at chart see patient lacks gamma protein.
(antibodies)
Looking at flow cytometry see lack of B
cells
Looking at flow cytometry again we can see
progenitor cells then there is a block as we do
not see mature cells
There are mutations in signalling protein
germline mutations in the BTK gene: Brutone
tyrosine kinase on the X-chrm
Bcell dev goes: Pro Pre small resting
immature B naïve mature B marginal
zone B/ through germinal center to be a
plasma cell or memory B
Pre-BCR signalling is required to get further
differentiation this doesn’t happen in
patients with genetic defects in tge IgH-Cu,
CD79a, CD79b, BTK, BLNK and λ14.1
Case study 2
Patient 1: recurrent bronchiolitis and
bronchopneumonia
Patient 2, 3 and 4: recurrent bacterial
infections from childhood
All patients: severely reduced serum IgG and
no CD19+ B cells (only CD20+)
No CD19 due to mutation causing early stop
codon. CD19 is used in signal transduction by
lowering the threshold for BCR signalling. To
look at the effect use intracellular calcium.
Patients lack of initial Ca2+ signalling
Patients have poor antibody responses but
there is still some shown by IgG spike
following rabies vaccine. These patients do
not develop memory.
A lack of CD19 interups antigen-dependent
developing in peripheral lymphoid tissue
naive mature B cells cannot go into the
germinal centre, we get no B and no plasma
cells.
TREATMENT FOR ANTIBODY DEFICIENCY
Document Summary
Markers: cd3 = tcr complex (tcell, cd19 = dev to mature b cells (not on plasma cells, cd20 = b cells (pro increases with maturity, cd16 on nkc. Note that on a normal mature b cell you will find cd19 and cd20. Sepsis is the presence and proliferation of bacteria in the blood. Low levels of immunoglobulins (increased risk of infection) Looking at chart see patient lacks gamma protein. (antibodies) Looking at flow cytometry see lack of b cells. Looking at flow cytometry again we can see progenitor cells then there is a block as we do not see mature cells. There are mutations in signalling protein germline mutations in the btk gene: brutone tyrosine kinase on the x-chrm. Bcell dev goes: pro pre small resting immature b na ve mature b marginal zone b/ through germinal center to be a plasma cell or memory b.
