Cytomegalovirus Infection Impairs the Mobilization of Tissue-Resident Innate Lymphoid Cells in Response to Acute Exercise

Boba

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https://pubmed.ncbi.nlm.nih.gov/34452400/


Abstract

Circulating immune cell numbers and phenotypes are impacted by high-intensity acute bouts of exercise and infection history with the latent herpesviruses cytomegalovirus (CMV). In particular, CMV infection history impairs the exercise-induced mobilization of cytotoxic innate lymphoid cells 1 (ILC1) cells, also known as NK cells, in the blood. However, it remains unknown whether exercise and CMV infection modulate the mobilization of traditionally tissue-resident non-cytotoxic ILCs into the peripheral blood compartment. To address this question, 22 healthy individuals with or without CMV (20-35 years-45% CMVpos) completed 30 min of cycling at 70% VO2 max, and detailed phenotypic analysis of circulating ILCs was performed at rest and immediately post-exercise. We show for the first time that a bout of high-intensity exercise is associated with an influx of ILCs that are traditionally regarded as tissue-resident. In addition, this is the first study to highlight that latent CMV infection blunts the exercise-response of total ILCs and progenitor ILCs (ILCPs). These promising data suggest that acute exercise facilitates the circulation of certain ILC subsets, further advocating for the improvements in health seen with exercise by enhancing cellular mobilization and immunosurveillance, while also highlighting the indirect deleterious effects of CMV infection in healthy adults.
 

Pyrrhus

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Circulating immune cell numbers and phenotypes are impacted by high-intensity acute bouts of exercise and infection history with the latent herpesviruses cytomegalovirus (CMV).
Here's one possibility that might be consistent with the above statement:
  • CMV seems to have a propensity to latently persist in immune cells called macrophages.
  • High-intensity exercise triggers macrophages in the blood to become activated and enter the muscle tissue to repair and re-build the muscle tissue in response to the high-intensity exercise.
  • Perhaps CMV is re-activated in these macrophages when they are activated and enter the muscle tissue?
Note that for historical reasons, macrophages have different names depending upon the part of the body in which they are found:
  • Macrophages in the blood are known as monocytes. (Monocytes are sometimes thought of as "pre-differentiated macrophages", although I'm not sure that this developmental distinction is terribly necessary.)
  • Macrophages that live in the epidermis are known as Langerhans cells.
  • Macrophages that live in the liver are known as Kupffer cells.
  • Macrophages that live in the brain are known as microglia.

cytotoxic innate lymphoid cells 1 (ILC1) cells, also known as NK cells
the mobilization of traditionally tissue-resident non-cytotoxic ILCs into the peripheral blood compartment.
Note to self:
I must learn more about this new characterization of NK cells.
 

Pyrrhus

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Note to self:
I must learn more about this new characterization of NK cells.
The Wikipedia page is quite informative here:
https://en.wikipedia.org/wiki/Innate_lymphoid_cell

Apparently the category of Innate Lymphoid Cells, which includes NK cells, only started to be appreciated circa 2008.

The sheer number and diversity of immune cells that we are now aware of has really skyrocketed in the last 20 years! (Especially with respect to tissue-resident immune cells like these!)