Characterization of cell lines is important to identify their origin and genetic stability. Techniques used include karyotyping, DNA content analysis, and DNA hybridization. Cultured cells have low cell-cell interaction, cannot perform differentiated functions, and are influenced differently by hormones and nutrients than in vivo cells. They also lack the 3D architecture of in vivo cells and favor proliferation of unspecialized cells. Growth parameters like population doubling time, confluence, cell cycle time, cell density, contact inhibition, and saturation density are measured. Tissue typing identifies species of origin using chromosomal or isoenzyme analysis. Tissue and cell line identity can be determined by markers like differentiated products, enzymes, and filament proteins. Transformed

2. INTRODUCTION
Characterization of cell lines is necessary
to identify linage of the cells, to the genetic
stability, phenotypic variation and to check
cross contamination.
Techniques used for chacterization-
karyotying, estimation of DNA content,
DNA hybridiztion.

3. CHARCTERISTIC OF CULTURED
CELLS
Cell to cell interaction is very low
Cannot perform differentiated and specialized
functions
Hormonal and nutritional influence on the
cultured cells differs from that on the invivo cells

4. 3-D architecture of the invivo cells is not
found in cultured cells.
The environment of the cultured cells
favours proliferation and spreading of
unspecialized cells.

5. 1)CELL-CELL INTERACTION
Cell–cell interaction-direct interactions between
cells that play a role in the development and
function of multicellular organisms.
Cell adhesion occurs through cell surface
receptors for the molecules in the extra cellular
matrix.
That cells secrete matrix proteins which spread on
the substrate. Then the cells bind to matrix
through receptors.

6. CELL ADHENSION MOLECULE
It occur between homologus cells.
Two types:
 Calcium dependent CAMs
 Calcium independent CAMs
E.g: Proteoglycans
Low affinity transmembrane and it can bind
to matrix molecules such as collagen and
growth factors.
It attached to the cytoskeletons of the
cultured cells.

7. 2)MEASUREMENT OF GROWTH PARAMETERS
OF CULTURED CELLS
POPULATION DOUBLING TIME (PDT)
 The time interval for the cell population to double
at the middle of the logarithmic phase.
CONFLUENCE
Denotes the cultured stages wherein all the
available substrate (growth area) is utilized, and
the cells are in the close contact with each other.

8. CELL CYCLE TIME (OR) GENERATION TIME
 The interval from one point in the cell division to
the same point in the cycle, on division later.
 Thus the cell cycle time is measured from one
point in the cell cycle until the same point is
reached again.
CELL DENSITY
 The number of cells per ml of the medium

9. CONTACT INHIBITION
 Inhibition of cell motility and plasma membrane
ruffling when the cells are in complete contact
with adjacent cells.
 This mostly occurs at confluence state and
results in the ceasation of the cell proliferation.
SATURATION DENSITY
 The density of the cells (cell/ml² surface area) in
the plateau phase.

10. 3)TISSUE TYPING
MORPHOLOGY OF CELLS
The composition of the cultured medium
and the alteration of the substrate inflence
the cellular morphology.
E.g: In tissue culture lab, the terms
fibroblastic and epithelial are used to
describe the appearance of the cells rather
than their orgin.

11. SPECIES OF ORGIN OF CELLS
It can be done by,
 Chromosomal analysis
 Electrophoresis of isoenzyme
 A combination of both these methods

12. IDENTIFICATION OF TISSUE OF ORGIN
Based on two characteristics it was
identified:
 The lineage to which the cells belong
The status of the cells i.e., stem cells,
precursor cells.

13. TISSUE MARKERS FOR CELL LINE
IDENTIFICATION
Differentiated product as cell markers-E.g:
Albumin for hepatocytes.
Enzymes as tissue markers-E.g: Alkaline
phosphate for enterocytes.
Filament protein as tissue marker-E.g: Desmin
for muscle cells.

14. TRANFORMED CELLS
TRANFORMATION- change in phenotype
due to the acquirement of new genetic
material.
It exhibit alteration in may characters
 Growth rate
 mode of growth
 longevity
 Tumorigenicity
 Specialized product formation

15. IDENTIFICATION OF SPECIFIC CELL LINES
Chromosome analysis
DNA detection
RNA and protein analysis
Enzyme activities

16. CONCLUSION
Biology and characterization of cultured
cells or cell lines is important for
dissemination of cell lines through call
banks, and to establish contacts between
research lab and commercial companies.