Science

Natural killer (NK) cells are the immune system’s first responders and play a vital role in the body’s protection.

Natural Killer (NK) Cells

NK cells are a type of cytotoxic white blood cell in the body that is active in both innate and adaptive immune responses. Their purpose is to find and destroy infected and abnormal cells, while preserving the body’s healthy cells and participating in the generation of immune protection.

NKGen Biotech’s NK cell immunotherapy was created to take advantage of the NK cells’ role in the body. By enhancing the body’s natural killers, we are maximizing the body’s ability to destroy infected and abnormal cells.

NK Cells Distinguish Stressed
Cells from Healthy Cells:

Ability to kill a broad range of tumor- and virus-infected cells
Mediate antibody-dependent cellular cytotoxicity (ADCC)
Additional regulatory capabilities after ADCC, mediated by secreted cytokines

Innate Lymphoid Cell:

NK cells make up 5 – 15% of the total lymphocyte population in normal healthy subjects
NK cells quick to respond upon exposure to a pathogen since no activation by specific antigens is required

Surface Phenotype:

Two cell surface markers are used to define NK cells
Lack of CD3 and presence of CD56

NK Cells and Their Function

NK cells are the first line of defense against infection, cancer and autoimmune disease. NK cells destroy their target by releasing toxic substances, perforin and granzymes, into the infected or abnormal cell resulting in target cell death.

As seen in the graphic, NK cells have multiple activating and inhibiting receptors to recognize dangerous cells. The balance between activating and inhibiting signals determines the NK cell’s response. When there is a mismatch between an inhibitory subgroup of KIR receptors on NK cells and HLA class I proteins on the surface of target cells (MHC Class I shown in red), the NK cells can get activated due to lack of inhibitory signals leading to killing of the target host cell. HLA class I molecules act as markers of “self” or indicating the cell is “not dangerous.”

NK Cells and Disease

NK cell activity is vital for maintaining health in many systems of the body, but their activity can wane during times of stress and fatigue. Infections, medications like steroids or immunosuppressants and disordered sleep can all decrease NK cell activity in the short-term. Long-term decreases in NK cell activity are experienced as a result of chronic medical conditions such as cancer, autoimmunity and neurodegeneration.

NK cells actively remove infected and abnormal cells and they can reduce autoimmunity by influencing and/or removing autoreactive T cells. NK cells help maintain the health of the body and are important protectors of the central nervous system, including the brain.