Mmhc Class 1 Essay

The activation and inhibition of Natural Killer cells is dependent on the balance between stimulation of activating and inhibitory receptors. If the stimulation of activating receptors is more prominent than NK cells will be activated, likewise if inhibitory receptors stimulation is dominant than NK cells activity will be suppressed.
For the immune system to work the first and foremost requirement is that it should be able to determine whether a cell is infected or not and then it can defend the body against pathogens. The same applies for NK cells. The mechanism of recognizing an “altered-self” state is thought to be involved. MHC Class 1 molecules displays non-self proteins to cytotoxic T cells resulting in response from the immune system against the foreign antigen. MHC Class 1 alleles are recognized by inhibitory receptors present on NK cells mainly KIRs, which explains why NK cells preferentially kill cells that possess low levels of MHC class I molecules. This mode of NK cell target interaction is known as "missing-self recognition". These receptors interact with MHC Class 1 molecules and control the killing mechanism of NK cells. This shows that cells possessing low
After a viral infection, infected cells release cytokines. These are stress molecules which notify the immune system cells about the presence of virus in the affected area. NK cells activating cytokines are IL-12, IL-15, IL-18, IL-12 and CCL5. Cytokines released form interferons and macrophages are a principle source of NK cell activation. They then prevent the viral infection from spreading so that cytotoxic T cells can eliminate them. IFNγ and TNFα are released by NK cells to curtail viral infection. Macrophages activated by IFNγ phagocytose and lyse the virus infected cells. TNFα on the other hand influences NK cells to kill tumor cells. It has been also found that deficiency of NK cells increases the chances of herpes