Hybridoma are cells that have been engineered to produce a desired antibody in large amounts. To produce monoclonal antibodies, B-cells are removed from the spleen of an animal that has been challenged with the relevant antigen. These B-cells are then fused with myeloma tumor cells that can grow indefinitely in culture (myeloma is a B-cell cancer). This fusion is performed by making the cell membranes more permeable. The fused hybrid cells (called hybridomas), being cancer cells, will multiply rapidly and indefinitely and will produce large amounts of the desired antibodies. They have to be selected and subsequently cloned by limiting dilution. Supplemental media containing Interleukin-6 (such as briclone) are essential for this step.
Selection occurs via culturing the newly fused primary hybridoma cells in selective-media, specifically media containing 1x concentration HAT for roughly 10-14 days. After using HAT it is often desirable to use HT containing media. Cloning occurs after identification of positive primary hybridoma cells. Clone by limited dilution. While some may believe that IL-6 is essential for this step, it is not necessary to add that expensive supplement, rather use 50% heat-inactivated FBS for the first week. Add 10% FBS DMEM to the clone culture plate after screening for single colony wells.
Method
HAT medium is used for preparation of monoclonal antibodies.Laboratory animals (eg. mice) are first exposed to an antigen to which we are interested in isolating anantibody against. Once splenocytes are isolated from the mammal, the B cells are fused with HGPRT negative, immortalized myeloma cells using polyethylene glycol or the Sendai virus. Fused cells are incubated in the HAT medium. Aminopterin in the medium blocks the de novo pathway. Hence, unfused myeloma cells die, as they cannot produce nucleotides by de novo or salvage pathway. Unfused B cells die as they have a short life span. In this way, only the B cell-myeloma hybrids survive. These cells produce antibodies (a property of B cells) and are immortal (a property of myeloma cells). The incubated medium is then diluted into multiwell plates to such an extent that each well contains only 1 cell. Then the supernatant in each well can be checked for desired antibody. Since the antibodies in a well are produced by the same B cell, they will be directed towards the same epitope, and are known as monoclonal antibodies.
The production of monoclonal anti-bodies was first invented by Cesar Milstein, Georges J. F. Köhler and Niels Kaj Jerne in 1975.
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