Core Framework & Diagram The Discovery of T Cells and B Cells

1 Min Read The Discovery of T Cells and B Cells

July 24, 2026

The Discovery of T Cells and B Cells

July 24, 2026

Care Framework & Diagram

Scientists spent seventy years figuring out that the immune system has two completely different types of lymphocytes

By the Editors Care Framework & Diagram

B Cells: Sold to the ‘Wrong’ Experiment BRUCE GLICK, 1955

Glick removes an organ (the bursa) from chicks as a class project, then sells the birds to a colleague’s unrelated salmonella experiment. The chicks make almost no antibodies and the batch dies — revealing, by accident, that this organ is essential for antibody production.

T Cells: ‘Did I Do Something Wrong?’ JACQUES MILLER, 1961, AGE 26

Miller removes the thymus from newborn mice to study a leukemia virus. Unexpectedly, the mice can’t reject foreign skin grafts and die easily from infections. He repeats the experiment twice more, certain he’s made a mistake — the result is the same each time. The thymus, it turns out, is essential to the whole immune system.

The ‘Nude Mouse’ — A Defect That Became a Tool NORMAN ISAACS, 1966

A single mutation removes both the thymus and body hair in the same animal. With almost no T cells, it can’t reject foreign tissue — making it the standard cancer-research animal for decades. Nearly every cancer treatment tested in animals has passed through a nude mouse.

HOW TOOLS SHAPED WHAT WE COULD SEE
In the 1960s, T and B cells looked completely identical under a light microscope. Monoclonal antibodies (1970s–80s), flow cytometry (1990s), and single-cell sequencing (2010s) each revealed a finer layer of what was hiding in plain sight.

STILL WAITING, STILL POSSIBLE

Jacques Miller received the Lasker Award in 2019, 58 years after his discovery — the Nobel still hasn’t come, and he’s still alive to receive it.
The ‘lymphocyte proportion’ on your own blood test report carries 60 years of this science behind it.

Frequently Asked Questions

Can T cells and B cells be distinguished visually?

Under ordinary light microscopes, no — they look almost identical, both small round lymphocytes. Distinguishing them requires flow cytometry or immunofluorescence techniques, by detecting specific protein markers on cell surfaces (T cells have CD3, CD4, or CD8; B cells have CD19, CD20) for identification. This is also why decades after microscopy was invented, scientists finally discovered they were actually two different types of cells — appearance deceived everyone.

Why hasn't Miller received a Nobel Prize?

This is an enduring 'regret' topic in the immunology world. Miller's discovery is recognized as one of the single most important discoveries in twentieth-century immunology; Nobel Committee candidate lists reportedly have included his name over the years, but he has not yet received it. Possible reasons: the Nobel Committee tends to favor work with clear 'mechanism' discoveries, while Miller's discovery was functional; and Nobel Prizes cannot be awarded posthumously — Miller is still alive, so a future award remains possible. He himself seems quite calm about this based on multiple interviews.

Humans don't have a bursa of Fabricius — so where do B cells develop?

Human (and other mammalian) B cells develop and mature in bone marrow — from hematopoietic stem cells in the bone marrow, through a series of developmental stages, finally becoming mature naive B cells entering the blood circulation. During fetal development, the liver is also a site of B cell development. Bone marrow, in terms of B cell development, is the mammalian functional equivalent of the 'bursa of Fabricius.'

If the thymus has shrunk, can T cells still be produced normally?

Partially. After adulthood, thymic atrophy does reduce fresh T cell production — this is one of immune aging (Immunosenescence)'s core mechanisms. But the body simultaneously has another mechanism to maintain T cell numbers: peripheral T cell homeostatic proliferation, where existing mature T cells self-replicate after receiving survival signals like IL-7, maintaining total numbers. This mechanism is quite effective in youth, but as age increases and thymic atrophy becomes more severe, T cell diversity (how many different antigens can be recognized) continuously declines — this is one of the fundamental reasons elderly people respond more weakly to novel pathogens (and vaccines). Regular exercise is proven to be the most effective single intervention currently for 'maintaining thymic function.'

Deep Read

Core Framework & Diagram The Discovery of T Cells and B Cells

1 Min Read The Discovery of T Cells and B Cells

The Discovery of T Cells and B Cells

1 Min Read The Discovery of T Cells and B Cells

The Discovery of T Cells and B Cells

Scientists spent seventy years figuring out that the immune system has two completely different types of lymphocytes

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