The First Nobel Prize in Physiology or Medicine: Kitasato Shibasaburo and the Foundations of Serum Therapy

The First Nobel Prize in Physiology or Medicine (1901)

The inaugural Nobel Prize in Physiology or Medicine was awarded in 1901 to the German physician and microbiologist Emil von Behring. The award honored his breakthrough discovery of serum therapy, particularly its application against diphtheria—a lethal infectious disease that claimed countless lives, particularly among children, in the late nineteenth century.

However, historians of science and biomedical researchers frequently revisit the 1901 award to examine a central historical figure: Dr. Kitasato Shibasaburo. Kitasato, a pioneering Japanese bacteriologist working alongside Behring in Berlin, co-authored the foundational work on serum therapy. His role in this scientific milestone makes him widely recognized as the Japanese scientist who was centrally tied to the very first Nobel Prize in Physiology or Medicine.

Kitasato Shibasaburo’s Landmark Discovery in Serum Therapy

In the late 1880s, Kitasato studied at the laboratory of Robert Koch at the University of Berlin. During his time in Germany, Kitasato achieved international scientific prominence through several major breakthroughs:

• Pure Culture of Tetanus Bacilli (1889): Kitasato was the first researcher in the world to successfully cultivate *Clostridium tetani* in an anaerobic environment, proving that the bacterium was the causative agent of tetanus.
• Discovery of Antitoxins and Serum Therapy (1890): Working in collaboration with Emil von Behring, Kitasato demonstrated that animals inoculated with non-lethal doses of tetanus toxin developed a protective substance in their blood. When serum from an immunized animal was transferred to a non-immunized animal, it conferred resistance and neutralized the toxin.

In December 1890, Behring and Kitasato published their joint landmark paper on tetanus immunity, establishing the concept of serum therapy. Shortly thereafter, Behring published a second paper applying the same principle to diphtheria. This therapeutic concept—passive immunization using blood serum—formed the foundation of modern immunology and provided humanity's first effective biological treatment against toxin-mediated bacterial diseases.

Why Was Kitasato Not Awarded the 1901 Nobel Prize?

When the Nobel Committee of the Karolinska Institute met to select the recipient of the first prize in 1901, Emil von Behring was named the sole laureate for his work on serum therapy against diphtheria. Kitasato was not included in the award, a decision that has prompted historical analysis for over a century.

Several key factors contributed to the Nobel Committee's decision at the time:

1. Focus on Diphtheria over Tetanus: While Kitasato led the primary experimental work on tetanus and co-authored the introductory serum therapy paper, Behring published the solo paper demonstrating serum efficacy against diphtheria. At the turn of the century, diphtheria was a rampant public health crisis causing widespread mortality in children across Europe, giving it greater perceived clinical urgency than tetanus. 2. Early Nobel Committee Procedures: In its inaugural year, the Nobel Committee favored recognizing single individuals rather than sharing prizes among multiple co-investigators, a practice that became more common in later decades. 3. Nomination Dynamics: Archival records from the Nobel Foundation indicate that the formal nominations submitted to the committee in 1901 heavily emphasized Behring's clinical application of diphtheria antitoxin rather than the joint fundamental discovery of humoral immunity.

Despite missing the prize, the global scientific community recognized Kitasato's foundational contributions. His research laid the conceptual groundwork that enabled Behring's clinical application.

The Scientific Legacy of Kitasato and Modern Biotechnology

After returning to Japan, Kitasato founded the Institute for Infectious Diseases (now part of the University of Tokyo) and later established the Kitasato Institute and the School of Medicine at Keio University. His scientific principles—rigorous isolation of biological agents, translational immunology, and public health application—remain foundational to modern biotechnology.

Today, passive immunization and antibody-based therapies have evolved from crude animal sera into engineered monoclonal antibodies, targeted immunotherapies, and advanced cell and gene therapies. The principle demonstrated by Kitasato and Behring in 1890—that biological products derived from cellular and humoral mechanisms can neutralize pathology—remains central to modern biopharmaceutical manufacturing and regenerative medicine.

Sources

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