Someone recently asked us if we can supply CD4+ memory T cells (yes, we can!) and inquired about the distribution of the central memory (TCM) subset, and our ability to isolate TCM cells.
Read on to learn more about memory T cells and our processes for isolating cell subsets.
About Memory T Cells
Memory T cells are T cells that have been activated by encountering an antigen. They get their name because these T cells “remember” the antigen from a previous encounter with a virus, infection, cancer, or vaccination. By definition, memory T cells have gone through multiple rounds of division and are differentiated to provide lasting protection from the virus or pathogen they have encountered.
Immunologists study these cells intensely due to their ability to provide long-lasting protection in the immune system. The memory T cell population has a few subsets that reside in different locations in the body and are assumed to have specific roles in maintaining the immune system.
Memory T Cell Subsets
There are several subsets of memory T cells, including:
Central Memory T Cells (TCM)
- Location: Lymphoid tissue, peripheral circulation
- Expression: CD45RO, CCR7, CD62L, CD44
- Function: Capable of robust proliferation to rapidly respond to immune challenges
Effector Memory T Cells (TEM)
- Location: Tissue, peripheral circulation
- Expression: CD45RO, CD44
- Function: Generate more effector cytokines
Tissue-Resident Memory T Cells (TRM)
- Location: Tissue where the virus or pathogen is first encountered
- Expression: CD69, CD103
- Function: Similar to TEM but specialized to their location
Stem Cell Memory T Cells (TSCM)
- Location: Peripheral circulation
- Expression: CD45RA, CCR7, CD62L, CD27, CD28, IL-7Rα, CD95, IL-2Rβ, CXCR3, LFA-1
- Function: Greater proliferative capacity than TEM and longer living than TCM
Differentiating Central Memory T Cells
We can distinguish between TCM and TEM cells through CD62L staining. CD62L is a molecule only found in TCM cells, not TEM cells. This allows you to see the proportion of TCM versus TEM in a sample for use in your immunotherapy research.