 Cell culture is the process by which prokaryotic, eukaryotic or plant cells are grown under controlled conditions. But in practice it refers to the culturing of cells derived from animal cells.  Cell culture was first successfully undertaken by Ross Harrison, 1907 & Carrel,  Roux in 1885 for the first time maintained embryonic chick cells in a cell culture.

 1878: Claude Bernard proposed that physiological systems of an organism can be maintained in a living system after the death of an organism.  1885: Roux maintained embryonic chick cells in a saline culture.  1897: Loeb demonstrated the survival of cells isolated from blood and connective tissue in serum and plasma.

 1903: Jolly observed cell division of salamander leucocytes in vitro.  1907: Harrison cultivated frog nerve cells in a lymph clot held by the 'hanging drop' method and observed the growth of nerve fibers in vitro for several weeks. (father of cell culture).  1910: Burrows succeeded in long term cultivation of chicken embryo cell in plasma clots.

 1911: Lewis and Lewis made the first liquid media consisted of sea water, serum, embryo extract, salts and peptones. They observed limited monolayer growth.  1916: Rous and Jones introduced proteolytic enzyme trypsin for the subculture of adherent cells.  1927: Carrel and Rivera produced the first viral vaccine - Vaccinia.

 1940s: The use of the antibiotics penicillin and streptomycin in culture medium decreased the problem of contamination in cell culture.  1948: Earle isolated mouse L fibroblasts which formed clones from single cells. Fischer developed a chemically defined medium, CMRL  1952: Gey established a continuous cell line from a human cervical carcinoma known as HeLa (Helen Lane) cells.

 1955: Eagle studied the nutrient requirements of selected cells in culture and established the first widely used chemically defined medium.(EMEM)  1964: Littlefield introduced the HAT medium for cell selection.  1965: Harris and Watkins were able to fuse human and mouse cells by the use of a virus.  1975: Kohler and Milstein produced the first hybridoma capable of secreting a monoclonal antibody.

 1982: Human insulin became the first recombinant protein to be licensed as a therapeutic agent.  1986: Lymphoblastoid γ-IFN licensed.  1987: Tissue-type plasminogen activator from recombinant animal cells became commercially available.  1989: Recombinant erythropoietin in trial.  1990: Recombinant products in clinical trial (factor VIII, HIVgp120, CD4, GM-CSF, EGF, mAbs, IL-2).

 um larger than bacteria or yeast  Eukaryotic  Cell membrane – no cell wall: shear sensitivity  Surface is negatively charged – grow on positively charged surfaces  Suspension cells or anchorage dependant cells.  80-85% water, 10-20% protein, and 1-5% carbohydrates.  Lipid bilayer cell membrane that is sensitive to shear.  Optimum growth at 37 o C

 In vitro cultivation of organs, tissues & cells at defined temperature using an incubator & supplemented with a medium containing cell nutrients & growth factors is collectively known as tissue culture.  Different types of cell grown in culture includes connective tissue elements such as fibroblasts, skeletal tissue, cardiac, epithelial tissue (liver, breast, skin, kidney) and many different types of tumor cells.

 Cell density must be controlled & optimized  Want cell density to be high enough to maximize production of (usually) protein product  But if cell density gets too high: › Nutrients in media get depleted › Waste products build up in media › In the case of some cells (such as animal cells), cell-to-cell contact can cause cells to stop dividing (“contact inhibition”)

Areas where cell culture technology is currently playing a major role-  Model systems for: - Studying basic cell biology - Interactions between disease causing agents and cells - Effects of drugs on cells - Process and triggering of aging & nutritional studies

 Toxicity testing: - Study the effects of new drugs  Cancer research: - Study the function of various chemicals, virus & radiation to convert normal cultured cells to cancerous cells

 Cells are cultured as anchorage dependent or independent  Cell lines derived from normal tissues are considered as anchorage-dependent grows only on a suitable substrate e.g. tissue cells  Suspension cells are anchorage-independent e.g. blood cells  Transformed cell lines either grows as monolayer or as suspension

 Anchorage – dependant  Anchorage - independant

 Most animal derived cells  Adhere to bottom of a flask and form a monolayer  Eventually cover entire surface of substratum  Proliferation then stops  Need to subculture cells at this point (remove to fresh medium)  Proliferation can begin again

 Cells associated with body fluid -blood cells  Grown in suspension  Will eventually need subculturing

 Laminar cabinet-Vertical are preferable  Incubation facilities- Temperature of o C for insect & 37 o C for mammalian cells, 95% air at 99% relative humidity. To prevent cell death incubators set to cut out at approx o C  Refrigerators- Liquid media kept at 4 o C, enzymes (e.g. trypsin) & media components (e.g. glutamine & serum) at -20 o C  Microscope- An inverted microscope with 10x to 100x magnification  Tissue culture ware- Culture plastic ware treated by polystyrene

 If working on the bench use a Bunsen flame to heat the air surrounding the Bunsen.  Swab all bottle tops & necks with 70% ethanol.  Flame all bottle necks & pipette by passing very quickly through the hottest part of the flame.

 Avoiding placing caps & pipettes down on the bench; practice holding bottle tops with the little finger  Work either left to right or vice versa, so that all material goes to one side, once finished  Clean up spills immediately & always leave the work place neat & tidy.

 Possibly keep cultures free of antibiotics in order to be able to recognize the contamination  Never use the same media bottle for different cell lines. If caps are dropped or bottles touched unconditionally touched, replace them with new ones  Necks of glass bottles prefer heat at least for 60 seconds at a temperature of 200 o C  Switch on the laminar flow cabinet 20 min. prior to start working  Cell cultures which are frequently used should be subcultered & stored as duplicate strains

 Glucose energy source up 55 mmol/L  Glutamine energy source 2-7 mmol/L  Aerobically metabolize to CO 2 or anaerobically to lactic acid.  Lactate and ammonium toxic byproducts of mammalian cell growth.  Lactic acid and ammonium inhibitory at 30 and 5 mmol/L, respectively.  Lactate reduces pH.

 Oxygen utilized at approximately pmol O 2 /cell 10-30% DO is non-limiting. Higher DO concentrations can be toxic, leading to oxidative damage.  Amino acids: cell line dependant, balance is critical.  Growth factors  Cytokines  Trace elements

Glucose Amino acids HCO 3 MammalianInsect 4 g/l 2.5 g/l g/l g/l Glutamine 1 g/l 3.5 g/l 0.35 g/l H 2 PO g/l 1 g/l pH Osmolarity 300 mOsm350 mOsm Salts Vitamins/Spore 4.5 g/l NaCl 1g/l MgSO4,KCl More Less

 Fetal Bovine Serum (FBS; also named as 'FCS')  widely used in animal cell culture as an essential supplement.  serum and protein free media have only been established for selected protocols.  by-product of the beef-packing industry, FBS can only be obtained where sufficient numbers of fetuses become available during the slaughtering process.

- Albumin - Immunoglobulins (IgG 75-85% of all Ig) - Fibrinogen - Alpha-1 antitrypsin - Alpha-2 macroglobulin - Transferrin - Alpha-2+ß-lipoproteins (LDL) - Alpha-lipoproteins (HDL) - Haptoglobin - Alpha-1 acid glycoprotein

 Ions Bicarbonate mM Chloride mM Sodium mM Potassium mM Calcium mM pH 7.4

 Mamallian cells grow best at 37 o C and 7.3 pH.  Bicarbonate based buffer to maintain a constant pH coupled with addition of base or acid when needed.  1-10% CO 2 in gas phase is also used to control pH.  CO 2 also important in the synthesis of purines and pyrimdines.

 CO 2 primes energy metabolism.  Excess CO 2 suppresses cell growth and can alter intracellular pH.  Osmolarity increases as pH is adjusted adjusted due to the addition of salts, too high osmolarity results in cell shrinkage and eventually lysis.

 Cell Products  Cell-Cell Interaction  Intracellular Activity  Intracellular Flux  Environmental Interaction

Category Advantages Physioco-chemical Interaction Control of pH, Temp., osmolarity, Dissolved gases Physiological conditionsControl of Hormones & Nutrient Concen. MicroenvironmentRegulation of matrix, cell-cell interaction, gaseous diffusion CharacterizationCytology & immunostaining are easily performed PreservationStored in Liquid N 2 Reduction of animal useCytotoxicity & screening of pharmaceutics Reagent savingReduced volumes, direct access, lower cost

Category Examples Necessary expertiseHandling Chemical contamination Microbial contamination Environmental controlWorkplace, Incubation pH control Disposal of biohazards Quantity & costCapital Equipment Consumables Medium, serum, plastics Genetic instabilityHeterogeneity, variability Phenotypic instabilityAdaption, selection Identification of cell typeExpression of markers, Histology, Cytology

 Cells when surgically or enzymatically removed from an organism and placed in suitable culture environment will attach and grow are called as primary culture  Primary cells have a finite life span  Primary culture contains a very heterogeneous population of cells  Sub culturing of primary cells leads to the generation of cell lines

 Cell lines have limited life span, they passage several times before they become senescent  Cells such as macrophages and neurons do not divide in vitro so can be used as primary cultures  Lineage of cells originating from the primary culture is called a cell strain

 A culture derived directly from a tissue  A stage from cell isolation to first subculturing Best resembling natural tissue Limited growth potential Limited life span May give rise to a cell strain or be immortalized Strain – a lineage of cells originating from one primary culture.

 Cell line: a permanently established cell culture that will proliferate indefinitely given appropriate fresh medium and space. › Unlike primary cells (directly from tissue), cell lines have been immortalized › Immortalization is a process that shares similarities with the transformation of a normal cell into a cancerous cell

 Primary culture: cell recently excised from specific organs of animals.  Secondary culture: cell line obtained from the primary culture. Can be adapted to grow in suspension and are non-anchorage dependant. Will only grow for about 30 generations.  Continuous, immortal, transformed cell lines: cells that can be propagated indefinitely (cancer cell lines are all continuous).

Different types of cell line produced from different tissues or organs. Broadly they are grouped into: - Finite cell line - Continuous cell line.

Finite cell line: Grow through a limited number of cell generations and have limited life. Grow slowly and form monolayer. Doubling time ranges from 24 to 96 hours. Anchorage dependent, contact inhibition and density limitation.

Obtained from either from transformed cell line in vitro or cancerous cells. Divides rapidly. Generation time hrs. No or reduced density limitation

 Most cell lines grow for a limited number of generations after which they ceases.  Cell lines which either occur spontaneously or induced virally or chemically transformed into Continous cell lines.

 Smaller, more rounded, less adherent with a higher nucleus /cytoplasm ratio.  Fast growth and have aneuploid chromosome number.  Reduced serum and anchorage dependence and grow more in suspension conditions. -ability to grow upto higher cell density -different in phenotypes from donor tissue -stop expressing tissue specific genes

 Mammalian cell line  animal cell line.  Insect, fish, crustacean cell lines are evolving technologies.  Baculovirus: virus that infects insect cells. Nonpathogenic to humans, has a strong promoter.  Insect cell lines are naturally continuous.  Most cell lines derived from ovaries or embryonic tissue.  Hybridoma cells: fusing lymphocytes (normal blood cells that make antibodies) with myeloma (cancer) cells.