My histology textbook says the following:

The pluripotential hemopoietic stemm cell (which resembles a lymphocyte) is a member of the null cell population of lymphocytes.

It then goes on to add:

There are three types of lymphocytes:

  • T cells
  • B cells
  • Null cells:
    • Pluripotential hemopoietic stem cells
    • Natural Killer cells

However, this is the only text I find that classifies Pluripotential hemopoietic stem cells as null cells. My question is: what are null cells? (and is this textbook accurate)

Thank you, jsx

  • $\begingroup$ When quoting, can you please make sure to quote exactly what is being said? It is part of academic ethics to not misquote (but typos happen, don't worry about it). I doubt your textbook says stemm cell and by this small typo of yours , it makes me wonder whether (which resembles a lymphocyte) was added by you or was in the original quotation. You also want to cite which textbook it is (and eventually add a link to it). Are the bullets a direct quote as well? If yes, you should start the lines with > to highlight that it is a quote. $\endgroup$
    – Remi.b
    Nov 13, 2017 at 18:40
  • $\begingroup$ This seems like either a very basic, very old, or very misleading textbook. The obvious meaning of "null cell" here is one that lacks both B cell receptors and T cell receptors. Such "null cells" would cover vastly more territory than the two sets mentioned, which is why I question the accuracy of the book. $\endgroup$
    – iayork
    Nov 13, 2017 at 18:44
  • 1
    $\begingroup$ Did you have a look at wikipedia > null cell? $\endgroup$
    – Remi.b
    Nov 13, 2017 at 18:44
  • $\begingroup$ @iayork I understand that that is the definition of a null cell. I'm using Gartner's 'Colour Atlas and Text of Histology'. So, null cells are simply cells that lack the receptors that T and B cells possess, and as such include the natural killer cells, killer cells, PHSCs and other cells too? $\endgroup$
    – jxs
    Nov 13, 2017 at 19:21
  • $\begingroup$ @jxs As far as I know it's obsolete terminology. It probably included all those, but just by accident, just as "horseless carriage" would include a Tesla and a Ferrari as well as a Model T. $\endgroup$
    – iayork
    Nov 13, 2017 at 19:40

1 Answer 1


Null cells are a "slang term" for cells of the lymphocyte progeny that are not APC (antigen presenting cells) and lack T and B cell receptors - therefore they are the natural killer (NK) cells.


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