Quantitative flow cytometry. Advancing the ability of flow cytometry to serve clinical and research purposes презентация

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My story : Biysk

Слайд 1Quantitative Flow Cytometry: advancing the ability of flow cytometry
to serve

clinical and research purposes

Darya Orlova

28 June, 2016


Слайд 2My story :

Biysk


Слайд 3My story :

Novosibirsk

Biysk


Слайд 4My story :

Novosibirsk
B.S. and M.S. in Physics


Слайд 5My story :

Novosibirsk
Ph.D. in Physics and Mathematics







Слайд 6My story :

Novosibirsk
Ph.D. in Physics and Mathematics

Brno
Ph.D. in Biophysics







Слайд 7My story :

Novosibirsk

Brno


Stanford, CA


Слайд 8What is the problem?
Flow cytometry is an essential tool for basic

immunological research, clinical discovery of potential therapeutics, development and approval of drugs and devices, disease diagnosis, and therapeutic treatment and monitoring.

However, the measurements made on different instrument platforms at different times and places often cannot be compared. Such discrepancies between and among measurements accompanied by discrepancies in data analysis procedures introduce uncertainty in diagnostic decisions, and impedes advances in basic science.

http://www.nist.gov/mml/bbd/bioassay/quantitative_flow_cytometry.cfm


Слайд 9To develop methods and procedures to enable quantitative measurements of biological

substances such as cells, proteins, etc.

By providing quantitative flow cytometry measurement solutions, we ensure that researchers can produce better data, better drugs are developed, and patients get better treatment in a clinical setting.

The objective :


Слайд 10Accurate classification and enumeration of cells with specific phenotypic characteristics.
Quantitation of

expression levels of surface and intracellular protein biomarkers.

Слайд 11Classification and enumeration of cells with
specific phenotypic characteristics
Marginal Zone

B cells

Follicular
B cells

Immature B + B-1 a cells


Слайд 12Schematic of the analysis package that statistical procedures are embedded

http://cytogenie.org/


Слайд 13Projection pursuit seeks one projection at a time
http://www.few.vu.nl/~tvpham/images/ppde.jpg
http://slideplayer.com/slide/4970323/#
Projection Pursuit


Слайд 14
why:
Curse of dimensionality
Less Robustness
Required number of events increases with dimensionality
Greater

computational cost
...

http://www.newsnshit.com/curse-of-dimensionality-interactive-demo/

Projection Pursuit


Слайд 15User-Guided Projection Pursuit


Слайд 16Walther G. et al, Adv Bioinformatics, 2009
Finding clusters by density based

merging (DBM)

Слайд 18How different are these two samples?


Слайд 19The index should:
possess the properties of a metric:
non-negativity d(x,y) ≥

0
identity of indiscernibles d(x,y) = 0, if and only if x = y
symmetry d(x,y) = d(y,x)
triangle inequality d(x,z) ≤ d(x,y) + d(y,z)
be robust with respect to small changes
be non-parametric
be computationally efficient

Goals:
quantitate differences between samples and provide a standard error
identify changes in joint expression of multiple markers
appropriately rank test samples based on the amount of deviation from controls

Quantification index allows biologically informative interpretation


Слайд 20Some test statistics are limited to univariate data, e.g., Kolmogorov-Smirnoff statistic

and Overton Subtraction (Sheskin, 2000)

Recent methods can be applied to multivariate flow cytometry
Probability Binning (Roederer et al., 2001)
Frequency Difference Gating (Roederer and Hardy, 2001)
Cytometric Fingerprinting (Rogers et al., 2008)
Quadratic Form Metric (Bernas et al., 2008)

How different are samples?
With respect to both the proportion of cells whose marker expression has changed and the magnitude of the change

Most of the current methods ask “Do samples differ?”


Слайд 21Probability binning plateaus but EMD increases monotonically as one population moves

further from the center of the other

Слайд 22EMD is the minimum cost of turning one pile of dirt

into the other where the cost is the amount of dirt moved times the distance by which it is moved

The biological interpretation of the EMD between two flow cytometry samples includes both the proportion of cells whose marker expression has changed and the magnitude of the change

Earth mover's distance (EMD)


Слайд 23Assume two distributions represented by signatures, P = {(p1,wp1),…,(pm,wpm)} and Q={(q1,wq1),…,(qn,wqn)}


where
pi,qi are bin centroids with frequencies wpi,wqi,
D = [dij] is the matrix of Euclidean distances between pi and qj for all i,j.
Find a flow F = [fij] between pi and qj that minimizes the total cost:

The optimal flow F between the source and destination signatures is determined by solving the linear programming problem.

EMD is then defined as a function of the optimal flow F=[fij] and the ground distance D=[dij]

Data were binned into the groups used in the signature according to (Roederer et al., 2001)

Earth mover's distance (EMD)
in terms of a linear programming problem


Слайд 24 Diagnostic tool for distinguishing cystic fibrosis (CF) from allergic bronchopulmonary

aspergillosis (ABPA) in CF

Surface CD203c in blood basophils after ex vivo stimulation with A. fumigatus (Af) allergen/extract (offending) or peanut (non offending) allergen. Gernez et al. J Cyst Fibros 11:502-10, 2012

Blood basophils from patients with ABPA are hyper-responsive to stimulation by Af allergen

Antibiotics

Corticosteroids
Anti-fungal
medicines


Слайд 25 Multiparameter diagnostic tool in CF and CF-ABPA
Compare basophil response to

stimulation with the A. fumigatus allergen/extract

Total white blood cells (FSС-A/SSC-A)→singlets (FSС-A/FSC-H)→CD41a--live (CD41a/live/dead)→
Dump--CD123++ (CD3, CD66b, HLA-DR/CD123)


Слайд 26EMD scores based on expression of two independent flow cytometry markers

more accurately distinguish allergic (CF-ABPA) from non-allergic (CF) patients

Слайд 27Cluster matching


Слайд 28Quantitation of expression levels of surface and intracellular protein biomarkers


Слайд 29

















































cell
cell
cell
We previously suggested an antigen concentration quantification approach which utilizes the

value of the binding rate constant for each particular monoclonal antibody-antigen reaction measured with flow cytometry

Antigen-antibody interactions on the surface of cells


Слайд 30



Experiment: kinetic of mean fluorescence
0.16 min
1 min
3 min
9 min
27 min

Beads or

blood
sample (fix)

Antibody*



Слайд 31


total number of receptor in the volume unit (free+occupied);






mean fluorescence value

of cell


Mathematical model: kinetic of mean fluorescence


Reaction rate constant
Initial antibody concentration
n – binding sites per one bead/cell

K+

A0


Слайд 32Obtained distributions of neutrophils on the number
(in logarithmic scale) of

FcgRIIIb receptors for different donors

The total number of cells is the same for each histogram



Слайд 33
As a solution to this problem we introduce a theoretical approach

allowing predicting the binding rate constant for changes in experimental conditions.

We verify our theoretical approach comparing the results to experimentally measured binding rate constants for classical examples of monoclonal antibody-antigen interactions under different temperature regimes.

However, application of such rate constant approach is currently limited by the lack of measured binding rate constant values for most antigen-antibody pairs of interest and changes in experimental conditions (temperature, viscosity, fluorescent labels, etc.)


Слайд 34Chothia et al., Nature, 1989


Слайд 35

Approximation of antigen binding site shape using rectangular
“binding spot” model



Слайд 36
From the binding rate constant k+, it was possible to estimate

the radius b of the binding site (a circular approximation of the shape of the site placed on a spherical reagent) using following expression

where η is the viscosity of the media, kB is the Boltzmann constant, T is the temperature; R1 and R2 are radii, N1 and N2 are valences of the first and second reactants, correspondingly.

The radius of antibody molecules can be estimated from the diffusion coefficient using Stokes–Einstein equation :


On the other hand, the diffusion coefficient of the molecule can be estimated using the known relationship between the diffusion coefficient (in cm2 s-1) and the molar mass (in Da), M, of a protein (in water at room temperature)



Слайд 37
Empirical binding rate constant values and corresponding calculated effective binding site

radii for 6 antigen-antibody complexes at room temperature

Слайд 38The rate constants estimated using binding site radius value for room

temperature are in good agreement with published empirical binding rate constants for different temperature regimes

Слайд 39Physics of chemoreception. HC Berg & EM Purcell, Biophys J 20,

93-219 (1977).

Electrical analogue


Слайд 40Antigen “effective binding site” radius as an equivalent of plate capacitor

capacitance

“Effective binding site” radius (b) can be calculated using the following expression:

where a and c are maximum length and maximum width (assuming a>c) of dominant amino acid residuals respectively (e.g. can be determine using HyperChem 7.5 software)


Слайд 41Functional epitope


Слайд 42Comparison of estimates for binding site radius electrostatic analogues with effective

binding site radii calculated using empirical rate constant values

Слайд 43
The rate constants estimated using binding site radius value for room

temperature are in good agreement with published empirical binding rate constants for different temperature regimes

*


Слайд 44Practical application in quantitative agglutination test
http://image.slidesharecdn.com/nephlerometryandturbidimetry-150203152442-conversion-gate02/95/nephlerometry-and-turbidimetry-6-638.jpg?cb=1422977133


Слайд 45Thank you!
Darya Orlova, Ph.D.
Stanford University School of Medicine
Genetics Department
Beckman Building,

Room B013
279 Campus Drive, Stanford, CA 94305
orlova@stanford.edu

Слайд 46[2] Moskalensky et al., 2015
[3] Xavier et al., 1998
[4] Xavier et

al., 1999
I5] Ito et al., 1995
[6] Raman et al., 1992
[7] Nekrasov VM et al., 2014
[8] Ibrahim, M., et al., 1998.
[9] Wibbenmeyer et al., 1999
[10] Sheriff et al., 1987
[11] Chacko et al., 1996
[12] Kam-Morgan et al., 1993
[13] Novotny, 1991
[14] Padlan et al., 1989
[15] Dall’Acqua et al., 1998
[16] Pierce et al., 1999

Слайд 47Number of possible 2-D combinations in n dimensional space:


Слайд 51Silhouette coefficient


Слайд 52
1. Calculate silhouette coef. (SC) For each pair of clusters+their noise.

Calculate % frequency for each cluster. Find the most separated (based on SC) pair of clusters with highest % frequency (cluster a and b).

2. Assign all other clusters on this 2D plot either to cluster a or cluster b based on SC.

a

b


3. Now you have only two clusters A and B (for each possible 2D plot).

4. Calculate SC between A and B. Calculate % frequency for A and B. Now you can rank all possible 2D plots based on then SC and % frequency distribution between A and B. On the first place should be 2D plot with SC closest to 1 and % frequency distribution closest to 50/50 between A and B.

5. Pick A or B from most highly ranked 2D plot, project A(or B) to all possible 2D plots and proceed recursively with the same procedure (1-5).


Слайд 53Summary of diffusion parameters for six well studied antigen-antibody complexes
in

water solution



Слайд 54Physics of chemoreception. HC Berg & EM Purcell, Biophys J 20,

93-219 (1977).



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