Köhler and Milstein fused B cells with cancer to mass-produce monoclonal antibodies

Every B lymphocyte makes exactly one antibody, honed to one target — then, being a terminally specialized white blood cell, it dies within days in culture. Myeloma cells, tumours of antibody-producing lines, grow forever in a dish, but nobody knows what their antibody binds. For decades biomedical researchers wanted the combination: unlimited quantities of an antibody raised against a target they had chosen. Sera from immunized animals gave messy, batch-varying mixtures of thousands of antibodies instead.

In 1975 Georges Köhler, a postdoc, and César Milstein, his group leader, at the MRC Laboratory of Molecular Biology in Cambridge made the combination real. They immunized a mouse, took its antibody-producing spleen cells, and fused them with cultured myeloma cells. The hybrids — hybridomas — survived and divided like the tumour while secreting the antibody dictated by the B cell. Selection arrangements let hybrid cells multiply but killed the unfused myelomas; the hybrids were then diluted so that colonies grew from single cells, and clones secreting the wanted antibody were identified.

The elegance is in the division of labour: the myeloma contributes only survival and endless division, the B cell only its one precise specificity. You can point the whole machine at any antigen you like — immunize, fuse, select, clone — and out comes a renewable production line for a single, defined antibody. The 1975 Nature paper described the recipe in a page and a half.

The Nobel Foundation later called hybridoma production one of the most important methodological advances in biomedicine of the 1970s: monoclonal antibodies opened new fields of research, enabled precision diagnosis, purification of substances like interferon through affinity chromatography, and early attempts at treating disease and transplant rejection.

Fuse an antibody cell with a cancer that never dies

Each parent supplies exactly what the other lacks, so the hybrid is more viable than either parent line: immortality plus chosen specificity in one genome.

The output is predetermined — you pick the antigen first and manufacture the probe afterwards, reversing the old order of making serum and finding out what it binds.

Growing colonies from single diluted cells guarantees every future batch is genetically identical, which is reproducibility at industrial scale.

It was a platform, not a reagent: the same four-step recipe works for any target, so one method spawned diagnostics, purification and drugs.

Two weaknesses can cancel: a cell that knows the target but dies, and a cell that lives but knows nothing. Pooling complementary strengths in a deliberate hybrid is a reusable design move.

Köhler and Milstein shared the 1984 Nobel Prize in Physiology or Medicine with Niels Jerne. Monoclonal antibodies moved from the Culture Collection into home pregnancy tests, diagnostic assays, affinity purification and, from the mid-1980s, therapeutic drugs; they became one of the largest classes of modern medicines. This archive's Celltrion REMSIMA case — the first biosimilar monoclonal approved in Europe — is a downstream consequence of the same 1975 technique.