Rat Hepatic Natural Killer Cells (Pit Cells) Express mRNA and Protein Similar to in Vitro Interleukin-2 Activated Spleen Natural Killer Cells

Liver NK cells expressing TRAIL are toxic against self hepatocytes in mice

“…27,28 Compared to freshly isolated peripheral blood and spleen NK cells, liver NK cells were found be more cytotoxic against various tumor cells. 29,30 Unlike freshly isolated spleen NK cells, liver NK cells have high levels of expression of mRNAs encoding for perforin, granzymes, and cytokines. 30 These facts suggest that liver NK cells have characteristics comparable to those of activated NK cells.…”

“…29,30 Unlike freshly isolated spleen NK cells, liver NK cells have high levels of expression of mRNAs encoding for perforin, granzymes, and cytokines. 30 These facts suggest that liver NK cells have characteristics comparable to those of activated NK cells. The present study has demonstrated that liver NK cells have significantly higher cytotoxicity against self-hepatocytes when compared to spleen NK cells even after activation with poly I:C, suggesting that the functional difference between liver NK cells and spleen NK cells is not merely derived from the difference in their activating states.…”

Comments on Augmentation of local antitumor immunity in liver by interleukin-2 gene transfer via portal vein: A possible explanation for contradictory in vivo and vitro results of interleukin-2 treatment in a rat model of colon carcinoma metastasis

“…5 Highly purified HD cells show a marked response to IL-2 in expressing cytotoxic factors, while LD cells show no or a low response. 6 For example, granzyme RNA (RNKP-1 and RNKP-5) is clearly upregulated in HD cells after IL-2 treatment, but not in LD cells. 6 Granzymes have been shown to be involved in the killing of colon carcinoma cells by hepatic NK cells.…”

“…6 For example, granzyme RNA (RNKP-1 and RNKP-5) is clearly upregulated in HD cells after IL-2 treatment, but not in LD cells. 6 Granzymes have been shown to be involved in the killing of colon carcinoma cells by hepatic NK cells. 7 Therefore, local IL-2 production in the liver, as applied in the study of Tanji et al, most likely activates the HD cells and to a much lesser extent the LD cells.…”

A Distinct Subset of Hyporesponsive Intrahepatic NK Cell is Partially Regulated ny IL-10: Implications for Liver Tolerance

“…Early reports of a liver-specific NK cell population identified in the rat liver were termed Pit cells, due to the observation of a large number of intracellular granules, which correlated with a high level of cytotoxic activity (Luo et al 2000;Nakatani et al 2004). Pit cells express CD69 and were described as an activated NK cell population (Luo et al 2001). However, data concerning cytokine production and receptor expression on Pit cells is limited.…”