Michael Sela (1924–2022): The Architect of Molecular Immunology
Michael Sela was a titan of 20th-century science whose work fundamentally reconfigured our understanding of the immune system. A chemist by training and an immunologist by necessity, Sela bridged the gap between these two fields, transforming immunology from a descriptive biological discipline into a precise molecular science. His research not only yielded profound theoretical insights into how the body recognizes foreign invaders but also led to the development of life-saving drugs for multiple sclerosis and cancer.
1. Biography: From Refugee to Research Pioneer
Born Mieczysław Salomonowicz in Tomaszów Mazowiecki, Poland, on March 2, 1924, Sela’s early life was defined by the upheaval of World War II. In 1935, his family moved to Germany, only to flee to Romania following the rise of the Nazi regime. In 1941, Sela emigrated to Mandatory Palestine.
Education and Early Career:
- Hebrew University of Jerusalem: Sela earned his M.Sc. in Chemistry in 1946.
- Post-War Europe: Briefly served as a delegate for the Jewish Agency in Italy, helping Holocaust survivors emigrate.
- The Weizmann Institute of Science: Sela joined the newly formed Weizmann Institute in Rehovot in 1950. He completed his Ph.D. under the mentorship of Ephraim Katchalski (who later became President of Israel and changed his name to Katzir).
Academic Trajectory:
Sela spent his entire professional life at the Weizmann Institute. He rose through the ranks to become the Head of the Department of Chemical Immunology (1963–1975) and eventually served as the President of the Weizmann Institute (1975–1985). During his presidency, he was credited with elevating the institute’s international profile and fostering an environment where basic research could be translated into industrial applications.
2. Major Contributions: Deciphering the Immune Code
Sela’s primary contribution was the introduction of synthetic antigens to the study of immunology. Before his work, scientists used complex natural proteins to study immune responses, which made it impossible to determine exactly which part of a molecule triggered an antibody reaction.
- Synthetic Polypeptides: Sela proved that synthetic molecules—specifically amino acid polymers designed in the lab—could provoke an immune response. This allowed researchers to vary the structure of the "invader" systematically to see what the immune system was actually "seeing."
- Genetic Control of Immune Response: By using these synthetic antigens, Sela (working with Baruj Benacerraf and others) discovered that the ability to respond to a specific antigen is genetically determined. This laid the groundwork for the discovery of the Major Histocompatibility Complex (MHC), which is crucial for organ transplantation and understanding disease susceptibility.
- Copaxone (Glatiramer Acetate): Applying his knowledge of synthetic polymers, Sela, along with Ruth Arnon and Devorah Teitelbaum, developed a synthetic molecule that mimicked the myelin sheath surrounding nerve fibers. This drug, Copaxone, became a primary treatment for Multiple Sclerosis (MS), helping to reduce the frequency of relapses in patients.
- Targeted Cancer Therapy: Sela’s later research focused on the Epidermal Growth Factor Receptor (EGFR). His work was instrumental in the development of Erbitux, a monoclonal antibody used to treat colorectal and head and neck cancers.
3. Notable Publications
Sela was a prolific author with over 800 scientific papers. Some of his most influential works include:
- "Science" (1960): Studies on the Chemical Basis of the Antigenicity of Proteins. This landmark paper introduced the use of synthetic polypeptides to analyze the nature of antigenicity.
- "Advances in Immunology" (1966): Immunological Studies with Synthetic Polypeptides. A definitive review that established the field of molecular immunology.
- "The Antigens" (1973–1987): Sela edited this multi-volume series, which served as the "bible" for immunologists for two decades.
- "Proceedings of the National Academy of Sciences" (1971): Suppression of experimental allergic encephalomyelitis by a synthetic polypeptide. This paper detailed the early success of the compound that would become Copaxone.
4. Awards & Recognition
Though the Nobel Prize famously eluded him (despite many in the field believing he deserved it alongside Benacerraf), Sela received nearly every other major scientific honor:
- Israel Prize in Life Sciences (1959): Awarded at the exceptionally young age of 35.
- Gairdner Foundation International Award (1967): For contributions to medical science.
- Wolf Prize in Medicine (1998): Shared with Ruth Arnon for their work on MS.
- Legion of Honour (France): Named an Officer (2011) and later Commander.
- International Memberships: He was a member of the U.S. National Academy of Sciences, the Pontifical Academy of Sciences, and the Russian Academy of Sciences.
5. Impact & Legacy
Michael Sela’s legacy is twofold: scientific and institutional.
Scientifically, he shifted immunology from a branch of pathology to a branch of molecular biology. His work on synthetic antigens provided the toolkit that allowed modern immunology to exist. Every time a vaccine is engineered or a monoclonal antibody therapy is developed, it stands on the foundation Sela built.
Institutionally, he was a champion of "blue-sky" research. He famously argued that the most practical applications (like Copaxone) often arise from pure, curiosity-driven exploration. Under his leadership, the Weizmann Institute became a global hub for biotechnology, proving that a small nation could lead in high-stakes global science.
6. Collaborations
Sela was a deeply collaborative scientist who believed in the power of the research group.
- Ruth Arnon: His most enduring partnership. Together, they spent over 30 years moving from the lab bench to the clinic to develop Copaxone.
- Ephraim Katzir: His mentor and later colleague, with whom he explored the chemistry of poly-amino acids.
- Christian Anfinsen: Sela collaborated with the Nobel laureate on protein folding, specifically using the ribonuclease enzyme as a model.
- Baruj Benacerraf: Though they worked in different countries, their intellectual exchange regarding the genetic control of immune responses was pivotal for the 1980 Nobel Prize in Medicine (awarded to Benacerraf).
7. Lesser-Known Facts
- Polyglot: Sela was fluent in seven languages (Polish, German, Russian, Italian, Hebrew, English, and French), which he used to foster international scientific diplomacy during the Cold War.
- The "Accidental" Drug: Copaxone was originally intended to induce MS-like symptoms in lab animals to study the disease. To the researchers' surprise, the synthetic polymer actually suppressed the disease. Sela had the insight to pivot the research toward a cure rather than a model.
- A Man of the Arts: Sela was a passionate supporter of the arts. He insisted that the Weizmann Institute campus be filled with sculptures and that scientific conferences be paired with classical music concerts, believing that creativity in art and science sprang from the same source.
- Scientific Diplomacy: He served as the President of the International Union of Immunological Societies and was a key figure in the European Molecular Biology Organization (EMBO), helping integrate Israeli science into the European community.