Blood Cells Traced to a Common Ancestor

By Ezzell, Carol | Science News, November 9, 1991 | Go to article overview

Blood Cells Traced to a Common Ancestor


Ezzell, Carol, Science News


After years of sifting through thousands of bone marrow samples, California researchers announced this week that they have identified a candidate "pluripotent" human blood cell - the elusive, primordial cell thought to serve as a fount replenishing red and white blood cells throughout a person's life.

The pluripotent blood cell has been the Holy Grail of hematology because it may hold the key to cures for a host of genetic disorders, leukemias and immune-system diseases such as AIDS. But the purported discovery has already generated controversy among hematologists, some of whom question the thoroughness of the experiments that led to the new finding.

Irving L. Weissman, a noted immunologist at Stanford University, reported the discovery at the 15th Bristol-Myers Squibb Symposium on Cancer Research, held in Seattle. Weissman told the conference that he and his colleagues at SyStemix Inc., a biotechnology company he founded in Palo Alto, Calif., had isolated a human pluripotent cell that can generate nearly every type of human blood cell when transplanted into the bone marrow of mice lacking an immune system. He claims that the cell is the most basic known "stem" blood cell, from which arises the family tree of more specialized blood cells.

To track down the pluripotent cell, the researchers used a series of antibodies against cell-surface proteins that identify the "cluster of differentiation" (CD) of each specific blood cell type. Blood cells that perform different jobs - such as antibody-producing B-cells, or invader-gobbling macrophages - wear different CD-protein uniforms, which are assigned a number as they are found by immunologists. Moreover, just as lieutenants's uniforms differ from those of generals, blood cells don new uniforms as they mature and are promoted to new roles.

Because Weissmann and his colleagues reasoned that blood-cell precursors must persist throughout life, they began their quest among a set of bone marrow cells that had already survived for months in their laboratory. They eventually narrowed their search to a subset of slow-growing cells that stained weakly with the dye rhodamine - an indication that the cell's energy-producing mitochondria were merely idling.

When the researchers added these human marrow cells, one by one, to connective-tissue cells taken from mouse marrow and grown in the laboratory, they found one type of cell that could give rise to all major blood-cell varieties. These cells stuck to a mixture of labeled antibodies that detected the CD34 protein and another protein - called Thyl - that is present on T-cells, white blood cells that mature in the thymus. The same cells also lacked a set of CD proteins, collectively known as the lineage determinants (Lin), normally found on mature blood cells. Weissman's group named the precursor cursor cells [Thyl.sup.+.Lin.sup.-CD34.sup+.]

To prove that these cells could give rise both to lymphoid cells (produced in the lymph nodes, thymus or spleen) and to myeloid cells (made in the bone marrow), the researchers injected some of the cells into the bone marrow of immunodeficient mice, and others into human thymus tissue transplanted into a second group of immunodeficient mice (SN: 9/24/88, p. …

The rest of this article is only available to active members of Questia

Already a member? Log in now.

Notes for this article

Add a new note
If you are trying to select text to create highlights or citations, remember that you must now click or tap on the first word, and then click or tap on the last word.
One moment ...
Default project is now your active project.
Project items

Items saved from this article

This article has been saved
Highlights (0)
Some of your highlights are legacy items.

Highlights saved before July 30, 2012 will not be displayed on their respective source pages.

You can easily re-create the highlights by opening the book page or article, selecting the text, and clicking “Highlight.”

Citations (0)
Some of your citations are legacy items.

Any citation created before July 30, 2012 will labeled as a “Cited page.” New citations will be saved as cited passages, pages or articles.

We also added the ability to view new citations from your projects or the book or article where you created them.

Notes (0)
Bookmarks (0)

You have no saved items from this article

Project items include:
  • Saved book/article
  • Highlights
  • Quotes/citations
  • Notes
  • Bookmarks
Notes
Cite this article

Cited article

Style
Citations are available only to our active members.
Buy instant access to cite pages or passages in MLA, APA and Chicago citation styles.

(Einhorn, 1992, p. 25)

(Einhorn 25)

1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25, http://www.questia.com/read/27419298.

Cited article

Blood Cells Traced to a Common Ancestor
Settings

Settings

Typeface
Text size Smaller Larger Reset View mode
Search within

Search within this article

Look up

Look up a word

  • Dictionary
  • Thesaurus
Please submit a word or phrase above.
Print this page

Print this page

Why can't I print more than one page at a time?

Help
Full screen

matching results for page

    Questia reader help

    How to highlight and cite specific passages

    1. Click or tap the first word you want to select.
    2. Click or tap the last word you want to select, and you’ll see everything in between get selected.
    3. You’ll then get a menu of options like creating a highlight or a citation from that passage of text.

    OK, got it!

    Cited passage

    Style
    Citations are available only to our active members.
    Buy instant access to cite pages or passages in MLA, APA and Chicago citation styles.

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn, 1992, p. 25).

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn 25)

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences."1

    1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25, http://www.questia.com/read/27419298.

    Cited passage

    Thanks for trying Questia!

    Please continue trying out our research tools, but please note, full functionality is available only to our active members.

    Your work will be lost once you leave this Web page.

    Buy instant access to save your work.

    Already a member? Log in now.

    Oops!

    An unknown error has occurred. Please click the button below to reload the page. If the problem persists, please try again in a little while.