Natural killer (NK) cells play a key role in the innate immune system. These lymphocytes react to certain infections and malignancies by direct cytolysis of infected or transformed cells and by secretion of potent immune mediators. NK cells have the ability to recognize foreign or stressed cells that lack antibodies and major histocompatibility complex (MHC) class I proteins on the surface, which would normally go undetected by other immune cells. However, NK cells express an array of inhibitory receptors that recognize self-molecules. If not restrained by inhibitory receptors recognizing MHC class I proteins on the surface of self-cells, NK cells are able to kill normal, healthy cells.
Human peripheral blood CD56+ natural killer cells are enriched by means of negative selection. Cells expressing CD3, CD4, CD14, CD19, CD20, CD36, CD66b, CD123, HLA-DR, and CD235a are depleted from the mononuclear cell fraction by using immunomagnetic particles leaving purified, untouched CD56+ natural killer cells. Our CD56+ natural killer cells are collected at FDA-licensed donor centers and further processed at our cell isolation laboratory. Each product is characterized by flow cytometry to ensure a highly pure and viable cell population. All donors are tested for HIV, Hepatitis B and C, WNV, CMV and other blood-borne pathogens.
Biospecimens are obtained from properly consented donors. We conform to HIPAA standards to protect the privacy of the donor’s personal health information.
Human Material Precaution
It is best to use caution when handling any human cells. We recommend all human cells should be handled as if potentially infectious following biosafety level 2 procedures. Even with infectious virus assays or viral antigen assays, a negative test result may leave open the possible existence of latent viruses.