> For the complete documentation index, see [llms.txt](https://docs.snomed.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.snomed.org/snomed-ct-specifications/snomed-ct-editorial-guide/readme/authoring/domain-specific-modeling/body-structure/index-1/cell.md).

# Cell

## Modeling of cells expressing antigens

As the cell hierarchy is primitive, careful attention is needed to manually identify and add the appropriate supertypes.

Undifferentiated cell concepts with a single positive or negative antigen expression (e.g. cell vs. lymphocyte or blast) are immediate subtypes of 362837007 |Entire cell (cell)|.

* For example,
  * 725316009 |Cell positive for CD1 antigen (cell)| Is a 362837007 |Entire cell (cell)|

Undifferentiated cell concepts with multiple positive or negative antigen expressions should be subtypes of the appropriate cell concepts with those same single and combinations of positive/negative antigen expressions.

![](/files/QpxfYIrEjWvSoaBTEpsl)

Differentiated cells concepts with positive or negative antigen expression(s) should be subtypes of both: a) the differentiated cell concept of differentiation; and b) the appropriate undifferentiated cell concept with the appropriate positive or negative antigen expression(s).

* For example,
  * 117507002 |FMC7+ lymphocyte (cell)| should be a descendant of 56972008 |Lymphocyte (cell)| and also 1373072009 |Cell positive for FMC7 antigen (cell)|.

{% hint style="info" %}
See also [*Naming Convention for Cells Expressing Antigens*](/snomed-ct-specifications/snomed-ct-editorial-guide/readme/authoring/domain-specific-modeling/body-structure/index/naming-convention-for-cells-expressing-antigens.md)
{% endhint %}


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