Natural killer cells


A subgroup of CD4+ T cells.

Able to kill infected or transformed cells without previous activation by inducing cytokine inflammatory responses.

Lymphocytes that are critical for innate immunity against malignant or virally infected cells.

The sales of the innate immune system play a major role in immune surveillance by targeting cancer or virally infected cells that down-regulate HLA class I molecules or expresses stress markers.

Can migrate from the blood in response to stress with interaction with tissue cells via histocompatibility antigens to control immune reactions.

Express CD4 CD8 or neither cell surface marker.

CD56+CD3- innate immune effector cells that recognize target cells that have cellular stress such as malignant transformation or viral infection.

About 90% of peripheral blood N K cells have a CD 56dim CD 16bright phenotype and/or characterized by high cytotoxic granule andperforin expression and lower cytokine secreting capacity.

Approximately 10% of the NK cell fraction express a higher number of cytokine and chemokine receptors and a lower amount of cytotoxic granules, a poorer cytotoxic capacity but a superior ability to produce abundant immunenoregulatory cytokines after activation.

Display killer immunoglobulin like receptors, natural cytotoxicity receptors and c-lectin receptors.

Activation results in release of proinflammatory cytokines, including gamma-interferon which stimulates other aspects of the immune system.

Many cells express restricted T-cell receptors Vα24-Jα18 and are called invariant T cell receptor positive natural killer cells.

A wide range of solid tumors and hematologic malignancies are associated with significantly impaired NK cell function.

NK cell deficiencies in part, are responsible for failure of antitumor immunity.

NK cell population deficiencies may be located in peripheral blood, and lymphoid organs and in the tumor itself.

NK dysfunctional can originate in the primary NK cell dysfunction such as imbalance receptor expression, impaired cytolytic capacity, or reduced cytokine secretion, by insufficient interaction with her other immune cells, such as impaired killing of dendritic cells, active immunosuppression, and NK cell resistance the mechanism by tumor cells.

In multiple studies NK cell populations point to a prognostic indicator as to patient survival and a predictor of therapy efficacy.

In AML treated with hematopoeitic stem cell transplantation from unrelated donors, but alloreactivity of donor NK cells exert potent anti-leukemic effect.

NK cell functions is controlled by inhibitory and activating signals processed by cell surface receptors, including that inhibitory and activating killer-cell immunoglobulin like receptors (KIRs) whose genes vary number in content from person to person.

Inhibitory KIRs recognize HLA class I ligand groups HLA-C1, C2, and Bw4, and mediate tolerance to self-HLA molecules on target cells.


NK cells from an allogeneic source, such as cord blood, can safely be administered without HLA matching, eliminating the need to produce are unique chimeric antigen receptor product for each patient. 

Allogeneic NK Cells are safe after infusion for adoptive immunotherapy in patients with cancer.

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