Scientists have discovered how natural killer cells affect the immune function of the liver

Tian Zhigang of the Department of Life Sciences and Medicine of the Chinese University of Science and Technology found that there are a group of special NK cells in the liver that can negatively adjust T-cell antiviral immune response, and revealed the mechanism of its function. The results were published in the journal Immunity, part of cell publishing group.
has unique immune tolerance properties and is the primary place where many viruses replicate in the body. Liver T cells often fail to produce an effective immune response to remove the virus, resulting in persistent infection. However, the regulatory mechanism of low antiviral capacity of T-cells in the liver is not very clear.
(NK) cells are important immune cells in the body and are considered circulating lymphocytes. Previous studies of circulating conventional NK cells (cNK) have suggested that they play an important role in fighting viral infections.
group first reported a unique group of NK cells (LrNK) settled in the liver internationally in 2013. They do not participate in blood circulation and show significant differences in gene and protein levels with cNK cells.
in the latest study, researchers used LrNK cell defect mice to conduct experiments that found that T-cells in the liver were more functional, liver damage was worse and the virus decreased after they were infected with the virus. For normal mice or mice with LrNK cell defects, external transfer of LrNK cells inhibits the antiviral response of T cells in the liver, while cNK cells promote T cell antiviral response. This suggests that LrNK cells and cNK cells play the opposite role in antiviral infections. LrNK cells inhibit the antiviral response of T cells in the liver, resulting in slower virus removal, while cNK cells speed up virus removal. In vitro experiments have further found that LrNK cells rely on a PD-L1 protein on their surface to inhibit the function of T cells in the liver.
The result system expounds the completely opposite function of LrNK and cNK cells in regulating T cell response, suggests that LrNK cells play an important role in the maintenance of the liver immune tolerance micro-environment, and provides a new basis for understanding the intrinsic relationship between NK cell sub-group composition and regional immune characteristic shaping. (Source: Yang Baoguo Yao Qiong, China Science Journal)
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