The Multiple Faces of the Decidual Natural Killer Cell
Article first published online: 28 FEB 2013
© 2013 John Wiley & Sons Ltd
American Journal of Reproductive Immunology
Volume 70, Issue 1, pages 1–9, July 2013
How to Cite
The multiple faces of the decidual natural killer cell. Am J Reprod Immunol 2013; 70: 1–9., .
- Issue published online: 11 JUN 2013
- Article first published online: 28 FEB 2013
- Manuscript Accepted: 29 JAN 2013
- Manuscript Received: 28 DEC 2012
The decidual NK (dNK) cell is called on to support placental growth by providing an array of growth factors that directly transform the spiral artery and direct trophoblast invasion. Successful transformation is dependent upon adequate stimulation paradoxically stimulating the cell for placental support rather than cytotoxicity. With the identification of its supportive role, the presence of an intact cytotoxic mechanism has been confusing. Investigators have found that the cell remains fully capable of cytotoxic responses particularly in response to pathogen-specific signals. We postulate a dual threshold model where moderate stimulation results in release of stimulatory factors supporting placentation while intense stimulation, particularly triggered through pathogen-specific receptors, restores the cell to its protective, cytotoxic, role. Individual dNK cells mature attaining the capacity to respond to the delivery of cognate signals. The process, known as ‘licensing’ tunes responsiveness to the degree to which stochastically selected inhibitory receptors block cytotoxic response to self. A changing licensing milieu within the decidua may result in altered and unsuitable receptor expression. We postulate that a heterogeneous population of dNK cells where cells inappropriately licensed for the milieu contributes to pathology.