In the early 1970s, the field of antibody research was restricted by an inability to generate, isolate as well as purify single antibodies of a known specificity. On one hand, immortal myeloma cancer cell lines were known to produce monoclonal antibodies or antibody fragments, though of unknown specificity. On the other hand, Norman Klinman and others had developed methods, such as in vitro antigenic stimulation, for cloning primary B cells that produced single antibodies of known specificity but were limited by low monoclonal antibody (mAb) yield and short cell lifespan. César Milstein’s lab ( the Medical Research Council Laboratory of Molecular Biology located at the University of Cambridge) had been studying the origin of antibody diversity for a number of years and at the time was using the technique of cell:cell fusion to study the potential role of allelic exclusion in antibody expression in myeloma cells.
Georges Köhler joined César Milstein’s lab as a postdoctoral fellow in 1974. Together they developed the idea of a hybrid cell resulting from a cell:cell fusion between an immortal myeloma cell and a short-lived antibody-producing B cell with a designed target specificity. These “hybridomas” could theoretically make monoclonal antibodies against any specific antigen. The scientists immunized BALB/c mice with sheep red blood cells (SRBCs), a target known to elicit a strong antibody response in vivo and fused the splenocytes with myeloma cells using inactivated Sendai virus particles, creating the world’s first hybridomas. Each hybridoma possessed the immortal growth feature of the myeloma cell and the antibody-producing feature of the plasma B cell. Köhler and Milstein screened for antibody target specificity by a plaque assay (lysis of SRBCs) and identified a number of hybridomas producing target-specific antibodies with varying effector functions. These hybridomas could be cloned and expanded in vitro, thus for the first-time enabling production of large amounts of target-specific monoclonal antibodies
I invite you to read the benchmark paper that not only led to Köhler and Milstein receiving the 1984 Nobel Prize in Physiology or Medicine, but which eventually set in motion an entire field within the biotech industry.