2008 PBL Cat_mech_r.qxd:PBL Catalog.mech 11/29/07 1:51 PM Page 52
Glossary
4-Parameter Curve Fit Four-parameter fit is a mathematical equation to fit Sigmoidal dose-response data in a non-linear relationship between the
response (Y) and the concentration (X) which is S-shaped. It can expressed in the following formula:
y =
a – d
+ d
1 + (X/c)
b
In this equation, the variable y represents the average response at dosage X, where a and d are the upper and lower asymptote
of response, respectively. The parameters c represents the dose level that is half-way between the values of a and d, i.e., the
point of inflection of the curve. The value b is a factor that describes the slope of the curve.
Antibody Affinity The affinity of an antibody is measured by the interaction between one epitope and one antibody binding site.
Antibody Avidity Avidity is a measurement of overall strength of the antibody-antigen complex. It takes three factors into account: antibody
epitope affinity, the valence of both the antibody and antigen, and the structural arrangement of the interacting parts
Antigen An antigen or immunogen is a molecule that stimulates an immune response.
B7-1 (CD 80) B7-1, also known as CD80, is a type I transmembrane glycoprotein and a member of the immunoglobulin superfamily of cell
surface receptors. It is a co-stimulating ligand for CD28 and CTLA-4. CD80 is expressed at high levels on resting peripheral
monocytes and dendritic cells and at very low density on resting B and T lymphocytes. It has been reported that Type II IFN
exerts regulatory effects on CD80 induction.
B7-2 (CD 86) B7-2, also known as CD86, is a type I transmembrane glycoprotein and a member of the immunoglobulin superfamily of cell
surface receptors. It is a co-stimulating ligand for CD28 and CTLA-4. CD86 is expressed at high levels on resting peripheral
monocytes and dendritic cells and at very low density on resting B and T lymphocytes. It has been reported that Type II IFN
levels may be affected by the presence of anti-CD86 antibodies.
Cytopathic Effect (CPE) The resulting death and lysis of cells in culture when challenged with a virus.
Cross Reactivity Cross-reactivity is defined as the ability of an antibody to react with similar antigenic sites on different antigens. When there is low
avidity or specificity of an antibody or where multiple antigens having identical or very similar epitopes, cross-reactivity may occur.
Density-Plot A density plot simulates three dimensions. In this type of display, the third parameter refers to the number of cells. Thus, the X
and Y values are the same as for a dot plot. The plot is graphed typically using colors which designate the relative numbers of
cells. Areas of higher density will have a different color than other areas.
Dot-Plot This type of graph is visualized as a dot where each dot corresponds to the passage of a single cell through the detector. The
information correlates to the different emission levels of X and Y for each cell. The collective intensities of each of the two
parameters distinguishes individual cell populations
Drift Effect An uneven optical density reading over the ELISA plate from one side to the other. A phenomenon usually caused by uneven air flow
in the laboratory, TMB substrate not at room temperature, or long time intervals between additions of reagents to the wells.
EC
50
The EC (also known as ED) is defined as the cytokine concentration at which the activity is 50% of the maximum response.
This method of expressing potency should only be used for cytokines whose dose-response curves are sigmoidal in shape.
The formula for converting the activity as an EC in ng/ml to specific activity in units/mg is:
1 x 10
6

ED
= specific activity (units/mg)
50
(ng/ml)
Edge Effect An increase or decrease in optical density of edge compared to non-edge wells on an ELISA plate. A phenomenon usually
caused by differences in temperature, light, or evaporation.
Endotoxin Endotoxins are potentially toxic, natural compounds such as lipopolysaccharide (LPS) found inside pathogens. The level of
endotoxin in PBL's products is < 1.0 EU/µg
Epitope The region of an antigen that binds to an antibody is called an epitope.
ERK The extracellular signal regulated kinase (ERK) are serine/threonine kinases that regulate gene expression in response to
numerous extracellular signals including mitogens, environmental stress, growth factors and cytokines. It remains unclear if
interferons are involved in the up or down-regulation of ERK1/2 phosphorylation and activity. Nevertheless, combinations of
ERK inhibitors and IFN have been shown to increase the antiproliferative activity of IFN.
Fluorescence-activated FACS is a specialized type of flow cytometry which can be used to separate heterogeneous mixtures of cells one cell at a time
cell-sorting (FACS) into subpopulations. Fluorescence-activated cell sorting is based upon specific light scattering and fluorescence
characteristics of each cell.
Fluorescein Isothiocyanate (FITC) FITC is a fluorescein derivative typically conjugated to proteins via primary amines (i.e., lysines). FITC is typically excited by
the 488 nm line of an argon laser, and emission is collected at 530 nm.
PBLInterferonSource Toll Free: 1 877- PBL-8881
52
Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62