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R L L OSWE ARK P L Cancer Institute aboratory Flow of Cytometry ISAC XX TUTORIAL Carleton C. Stewart Sigrid J. Stewart
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ANTIBODY BINDING TO CELLS RPCI LFC
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Fc Fab Light Chain Kappa or Lambda IgG1 IgG2a IgG2b IgG2c IgG3 IgM IgA IgD IgE ANTIBODY STRUCTURE 1000 EPITOPES/ANTIGEN 2 LIGHT CHAINS 10 HEAVY CHAINS 20,000 CLONES Heavy Chain ssss ssss ssss papainpepsin ssss
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K f range is usually ~ 10 6 K r range is usually ~ 10 -3 K a = K f /K r = 10 6 /10 -3 = 10 9 KfKf KrKr Ab + Ep AbEp THE LAW OF MASS ACTION X[Ab] [Ep] RATE f = K f X[AbEp] RATE r = K r AT EQUILIBRIUM RATE f = RATE r = 0 and [AE]=Ka[Ab][Ep]/(1+Ka[Ab])
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Specific: Fab to epitope Fc to Fc receptor binding is high affinity and saturable Non Specific: binding is low affinity and not saturable WAYS ANTIBODIES BIND TO CELLS RPCI LFC
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Specific Activity is the concentration of bindable antibody to its epitope divided by the protein concentration. 2 [F(ab')] SA = (protein) RPCI LFC
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Reasons Antibodies do not bind to cells: overconjugation not purified degradation of binding site aggregation RPCI LFC
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STORING OF ANTIBODIES : Proteases destroy antibodies in: ascitic fluid serum bacteria Use sodium azide Use highly purified albumin or gelatin as carrier Purify antibodies immediately RPCI LFC
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1 x 10 -11 1 x 10 -10 1 x 10 -9 1 x 10 -8 1 x 10 -7 Ka=10 7 Ka=10 8 Ka=10 9 Ka=10 10 Ka=10 11
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EFFECT OF AFFINITY CONSTANT ON ANTIBODY BINDING Affinity Constant (L/M) 40 60 80 100 ---- 10 7 10 8 10 9 10 10 11 percent free
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0.010.11101001000 ANTIBODY ( g/ml) 1000 10 1 0.1 0.01 0.001 0.0001 MEASURED BINDING SPECIFIC BINDING NON-SPECIFIC BINDING Ka = 5 x 10 4 Ka = 5 x 10 8 ANTIBODY BINDING TO MEMBRANE ANTIGENS AMOUNT BOUND (ng/ml)
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MEASURED BINDING SPECIFIC BINDING NON-SPECIFIC BINDING Ka = 5 x 10 4 Ka = 5 x 10 8 ANTIBODY BINDING TO INTRACELLULAR ANTIGENS ANTIBODY ( g/ml)
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1000100 0.0001 0.001 ANTIBODY BINDING TO INTRACELLULAR ANTIGENS HIGH AFFINITY ANTIBODY ANTIBODY ( g/ml) AMOUNT BOUND ( ng /ml) 10 2 1 0.1 0.01 0.0010.010.1110 MEASURED BINDING SPECIFIC BINDING NON-SPECIFIC BINDING Ka = 5 x 10 4 Ka = 5 x 10 9
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SPECIFIC AND NON-SPECIFIC ANTIBODY BINDING (MEMBRANE) Specific Binding high affinity Ka = 10 8 - 10 10 for Ka = 5 x 10 8 saturation 1.0 µg/ml (0.1 µg/test) Non-Specific Binding low affinity Ka < 10 5 for Ka = 5 x 10 4 saturation 90 µg/ml (9 µg/test)
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SPECIFIC AND NON-SPECIFIC ANTIBODY BINDING (INTRACELLULAR) Specific Binding high affinity Ka = 10 8 - 10 10 for Ka = 5 x 10 8 saturation 0.1 µg/ml (.01 µg/test) Non-Specific Binding low affinity Ka < 10 5 for Ka = 5 x 10 4 saturation 90 µg/ml (9 µg/test)
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TITERING ANTIBODIES RPCI LFC
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MEMBRANE EPITOPES RPCI LFC
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876543210 2 3 4 5 Dilution Signal to Noise TITER MEMBRANE ANTIGENS
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ng/test ratioratio titer non-specific and specific binding
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CD4 FITC NUMBER OF CELLS Verification of Specific Binding
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INTRACELLULAR EPITOPES RPCI LFC
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destruction of epitope by denaturation loss of antigen by extraction masking epitope by cross-linking non-specific binding due to low affinity antibody by manufacture cross-reacting products by GOD FACTORS THAT AFFECT DETECTION AFTER FIXATION
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positive target cell lineage for antibody genotypically identical negative target cell lineage several different surrogate positive target cell lineages several different negative target cell lineages VERIFYING ANTIBODY SPECIFICITY CELLS
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western blot evaluation of Ka VERIFYING ANTIBODY SPECIFICITY PROCESS
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In the beginning there is a high extracellular antibody concentration.
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Antibodies diffuse relatively fast into the cell down the electrochemical gradient and bind specifically and non- specifically.
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BARRIERS TO INTRACELLULAR STAINING immobilized epitope decreases antibody binding affinity molecular crowding limits diffusion fixation induced epitope degradation fixation induced epitope obstruction
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BARRIERS TO SPECIFIC BINDING molecular crowding increases non-specific binding NSB reduces effective antibody concentration washing efficiency reduced due to slow off-rate multiple targets specificity with different epitope affinities (e.g. multiple bands on a western blot)
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So, what is the answer? Only one. Antibodies of high affinity so that there is a low free antibody concentration to begin with!
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10 1 2 3 4 1 µg MCF Ab 278 IC 5.8 isotype control antibody cytokeratin.3 µg MCF Ab 100 IC 3.6 10 1 2 3 4.01 µg MCF Ab 25.7 IC 2.6 number INTRACELLULAR ANTIGENS
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6543210 0 10 20 30 40 50 60 Dilution Signal to Noise TITER INTRACELLULAR ANTIGENS
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ANTIBODY BINDING RPCI LFC
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SIDE SCATTER PE-CD19PE-CD19 Differing Monoclonal Antibody Epitope Binding
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PE-CD69PE-CD69 FITC-CD69FITC-CD69 CD3 Importance of Fluorochrome Intensity
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No BFA With BFA CD4 Effect of the Drug Brefeldin A on Membrane CD69 Expression CD69CD69 CD69CD69
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TANDEM DYES RPCI LFC
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PE-fluorescence Variation In Compensation For PE-CY5 Reagents
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PE-fluorescence 8 hours in dark 8 hours in light TC-CD45 TC-CD3 Effect Of Light Exposure on PECY5 Tandem Fluorescence
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ABC PerCP-CD4 PECY5-CD4FSC SSCSSC CD25CD25 CD25CD25 PECY5 Binding to Monocytes
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BLOCKING IS IMPORTANT RPCI LFC
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DIRECT IMMUNOFLUORESCENCE STAINING NO BLOCKING Primary Antibody: murine monoclonal antibody A epitope FcR Fab Fc Fab Fc Fab Fc Fab Fc Fab Fc BCD %+=75
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DIRECT IMMUNOFLUORESCENCE STAINING NO BLOCKING Primary Antibody: murine monoclonal antibody A epitope FcR Fab Fc Fab Fc Fab Fc Fab Fc Fab Fc BCD %+=75
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ISOTYPE CONTROL- myeloma protein AUTOFLUORESCENCE CONTROL %+=50 %+=0 %+=75%-50=25%
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BLOCKING WITH GOAT IgG goat IgG A epitope FcR BCD Fab Fc Fab Fc %+=50
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INDIRECT IMMUNOFLUORESCENCE STAINING NO BLOCKING Primary Antibody: murine monoclonal antibody Second Antibody: fluoresceinated goat anti-mouse IgG F(ab') 2 V m m F V FcR epitope Fab Fc m m m F Fab Fc m Fab Fc m m m F Fab Fc m m m F Fab Fc m m m F
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INDIRECT IMMUNOFLUORESCENCE STAINING NO BLOCKING Primary Antibody: murine monoclonal antibody Second Antibody: fluoresceinated goat anti-mouse IgG F(ab') 2 V m m F V FcR epitope Fab Fc m mmm m m m F Fab Fc m Fab Fc m m m F Fab Fc m m m F Fab Fc m m m F m directly labeled primary
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INDIRECT IMMUNOFLUORESCENCE STAINING BLOCKING with mIgG Primary Antibody: murine monoclonal antibody Second Antibody: fluoresceinated goat anti-mouse IgG F(ab') 2 V m m F Fab Fc m V FcR epitope Fab Fc m m m F Fab Fc m Fab Fc m Fab Fc m m m Fm m Fm m F mmmmm
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add Mab Fab add fluoresceinated goat anti-mouse IgG F(ab') 2
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VERIFICATION OF BLOCK 1. FcR and non-specific binding FL-MAB + PE-mIgG 2. goat IgG + FL-MAB + PE-mIgG
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EFFECT OF BLOCKING ON ANTIBODY BINDING TO MONONUCLEAR CELLS LOG FLUORESCENCE CELL VOLUME
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number TOTAL A B C D channel number
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variation in gamma 1 myeloma protein binding to macrophages mopc myeloma protein
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VIABILITY IS IMPORTANT RPCI LFC
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ANTIBODIES BIND NON- SPECIFICALLY TO DEAD CELLS FL-KAPPA PE-LAMBDA dead cells ALL CELLSVIABLE CELLS AB
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lysed, washed cells + 5 µg EMA 10 min. 18 cm. EMA PROCEDURE WASH, FIX, AND ANALYZE 1 3 2
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EVALUATING VIABILITY WITH ETHIDIUM MONOAZIDE SSCSSC FSC % dead in gate = 2% FSC SSCSSC EMAEMA % dead = 12%
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Ab1 Ab3Ab3 Ab2Ab2 AB Effect of Dead Cells and Antibody Affinity on Immunophenotyping
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COMPENSATION RPCI LFC
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emission intensity wavelength FLBFLA
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-/\/\/\/\/\- - - + + FLBFLB A%B B%A 0 %B FLAFLA Opamp A optical filters PMT & preamp 20 %A Opamp B - - + + FLBFLB A%B B%A 5 %B FLAFLA Opamp A optical filters PMT & preamp 0 %A Opamp B -/\/\/\/\/\-
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+ = FLBFLB FLAFLA - - + + A%B B%A 5 %B Opamp A 20 %A Opamp B + = + = + =
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Uncompensated vs Compensated FL1 FL2
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FL1 FL2 COMPENSATION IS INTENSITY DEPENDENT uncompensated partially compensated fully compensated FL2
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COMPENSATE INSTRUMENT USING STAINED CELLS 1. Adjust PMT voltages using unstained cells 2. Adjust compensation for each fluorochrome
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R1 R2 R3 R4 R5 R6
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R3 A C B D
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FSC SSC R1 R2R3 R4 FITC-CD45 PE-CD4 PE-CY5-CD8 PE-CD4 R4R5 R6 PE-CY5-CD8 APC-CD8 R8 R9 R10 COMPENSATION UP TO FOUR COLORS WITH TWO LASERS
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