Modifications of hybridoma technology which improve the yield of monoclonal antibody producing cells.

Several modifications at various stages of the standard hybridoma technique were found to increase the yield of monoclonal antibody-producing cells. Lymphocytes obtained from draining lymph nodes of mice immunized over a 10 day period with antigen injected into the foot pads were used for cell fusion. Preincubation of myeloma cells with lymphocytes in the presence of 0.25% polyethylene glycol at 37 degrees C for 90 min increased the yield of antibody-secreting hybrid colonies ten times. The use of conditioned medium from cultivated rat thymocytes ('lymphokines') as a supplement to cultivation medium made it unnecessary to use feeder cells, and increased the growth rate of the hybridomas. No change of the culture fluid was needed during the time which was necessary to grow up the cells to be tested for monoclonal antibody production. By a combination of the described procedures, the time required from the start of immunization to the screening for positive hybridomas was shortened to 23 days.