American transplant congress
American Transplant congress is held annually, this year (2017) it was held in Chicago, Illinois, in McCormick place-Lakeside center from April 29 to May 3.I presented my research in poster session on 1-st of May. The research which I presented is focused on beneficial effects of immunosuppressive drug, mTOR inhibitor – everolimus.
The immunosuppressive regimen currently used after organ transplantation reduces adaptive components. Therefore, the innate immune cells play pivotal roles in immune surveillance and defense against microbes and neoplastic cells after transplantation. Although the mammalian target of rapamycin inhibitor (mTORi) is known as an immunosuppressive drug as well as a molecular targeting anti-cancer drug, its effects on innate immune cells are unclear. In this study, we analyzed the influence of mTORi on Natural Killer (NK) cell subpopulations in mice.
C57/BL6 mice were treated by intraperitoneal injection of mTORi (0-0.25mg/kg) for 7 days. Twenty four hours after the last injection, liver mononuclear cells (LMNCs), splenocytes and peripheral blood (PB) mononuclear cells were collected. The proportion of NK cells and various functional molecules on NK cells were analyzed by flow cytometry.
The cytotoxic activity of liver NK cells against hepatocellular carcinoma were analyzed by 51Cr release assay. The proportion of TCR-NK1.1+NK fraction in LMNCs did not differ in both mTORi-treated and -untreated groups (11±0.35% vs 11.3±1.6%, respectively). However, mTORi significantly upregulated the expression level of TRAIL on liver NK cells (25.6±1 vs 18.5±4.76, p =0.03). Expression of NKp46 and CD69 was also higher in mTORi-treated group (117.65±3.7 vs 96.16±3.45, 54.1±6.04 vs 46.8±12.15, respectively). The proportion of NK cells, expression of their activation markers in the spleen and PB was not affected by mTORi treatment. Liver NK cells from mTORi treated mice showed significantly higher cytotoxicity against TRAIL-sensitive Hepa1-6 cells (30.1% ± 13 vs 13.5 %± 6).
mTOR inhibitor has ability to enhance liver resident NK cell activity. This result suggests that mTOR inhibitor might be useful to maintain anti-microbe and anti-tumor immunity even under immunosuppressive condition after transplantation.
I attended almost all session regarding liver and kidney transplantation. The most interesting for me was sessions on new methods of diagnostic and preventing, treating the rejection and also presentation about immune tolerance. Discussion during poster session gave me ideas for future research . Definitely, this kind of congresses push ourselves to research more, to learn more.