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Drug Res (Stuttg). 2014 Jun;64(6):281-6. doi: 10.1055/s-0033-1358465. Epub 2013 Oct 23.

Augmenting the expression of NKp44 molecule and the natural killer activity in peripheral blood mononuclear cells from patients with malignant colorectal carcinoma.

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  • 1Department of Immunology, Faculty of Medicine, Dezful University of Medical Sciences, Dezful, Iran.
  • 2Department of Surgery, Zanjan University of Medical Sciences, Zanjan, Iran.
  • 3Department of Immunology, Faculty of Medicine, Rafsanjan University of Medical Sciences, Rafsanjan, Iran.
  • 4Department of Internal Medicine, Dezful University of Medical Sciences, Dezful, Iran.
  • 5Department of Social Medicine, Faculty of Medicine, Zanjan University of Medical Sciences, Zanjan, Iran.



NKp44 and NKG2D are of the main NK activating receptors involved in recognition and killing of tumors. Here we studied the stimulatory effects of PHA and/or K562 cell line on induction of NKp44 and NKG2D expression and the NK activity of PBMCs from patients with colorectal carcinoma (CRC).


Peripheral blood samples were collected from 10 patients with CRC. The peripheral blood mononuclear cells (PBMCs) from each patient received a single stimulation with PHA or double stimulation with PHA and irradiated K562 cell line (iK562). The expression of CD56, NKG2D and NKp44 were detected by flowcytometry. The NK activity of PBMCs against a colorectal carcinoma cell line named as SW742 was determined with 51Cr-release assay.


Double stimulation of PBMCs with PHA+iK562 significantly augmented the number CD56(+) cells compared to PHA alone and non-stimulated PBMCs (P<0.000, P<0.0000; respectively). A single stimulation of PBMCs with PHA resulted in an enhancement in NKG2D and NKp44 expression from 16.6±3.3% (for non-stimulated PBMCs) to 42±5.6% and 48.1±3.8% respectively (p<0.05). Double stimulation of PBMCs augmented the NKp44 expression significantly in comparison with single stimulation with PHA (73.6±12%, p<0.05). Double stimulation of PBMCs significantly enhanced the NK activity against SW742 target cells compared to single stimulation with PHA (p<0.05).


Our results demonstrated that the mitogen and iK562 exposure to PBMCs can significantly improve NK activity which is co-related to the higher expression of NKp44 and NKG2D. These data may help to improve cancer immunotherapy protocols.

© Georg Thieme Verlag KG Stuttgart · New York.

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