Researchers are studying the importance of white adipose tissue and its role in storing memory T cells.
The idea that if you don’t eat enough, you’ll get sick may be true in some ways, but there is new information available revealing that the immune system may have a strategy to keep fighting infectious agents even when food is scarce.
Researchers at the National Institute of Allergy and Infectious Diseases found that white adipose tissue has important immune functions imparted by stored memory T cells and even by factors within adipocytes. They conducted studies to determine if the harboring of memory T cells by adipose tissue is associated with maintaining immune memory during reduced calorie intake.
The location of memory T cells was determined in fasted (12 hr) mice infected with Yersinia pseudotuberculosis or Toxoplama gondii. After the mice recovered from infection, a significant level of memory T cells were produced in white adipose tissue. Exposing the mice to the same infectious agent again led to a stronger memory T-cell response, and the T cells in white adipose tissue responded more strongly than T cells in other body areas.
Also, adipocytes expressed antimicrobial genes in the presence of activated T cells, adding more to the infection-fighting power of the adipose tissue. These results are in line with past observations of increased T cells in fat-cell enriched bone marrow under conditions of reduced food intake.
Since it has already been shown in past studies that those who are obese tend to have altered inflammation levels that can dampen immune function, a balance of fat tissue and maintenance of a healthy weight or body mass index are important for optimal immune function. However, the function of white adipose tissue in preserving immune function during states of low energy availability is a valuable mechanism to protect from infectious exposures during states of malnutrition.
The research team also found that white adipose tissue is an important location for memory T cells in nonhuman primates. Whether this holds true for humans remains to be determined. In the meantime, understanding the role of white adipose tissue in immunity can help develop ways to approach or enhance cancer therapy with nutritional modification.
Resource: Memory T cells shelter in bone marrow, boosting immunity in mice with restricted diets. (2019). National Institutes of Health (NIH). Retrieved 22 October 2019, from https://www.nih.gov/news-events/news-releases/memory-t-cells-shelter-bone-marrow-boosting-immunity-mice-restricted-diets