Killing Effect Of Natural Killer Cells Combined With PD-1 Monoclonal Antibody On Colon Cancer Cell Lines

Objective:To establish a method for culturing natural killer cells(NK)in vitro;To explore the effect of monoclonal antibody against programmed cell death protein-1(PD-1)on the anti colon cancer cell line of NK cells;To compare the killing effects of NK cells on three colon cancer cell lines with different degrees of differentiation.Method:1.The proportion of NK cells detected by flow cytometry expanded from 0days(7.23% ± 2.60%)to 14 days(81.01% ± 11.30%).2.The killing effect of NK cells on colon cancer cell line Caco-2 decreased with the increase of effect target ratio(E: T);The killing effect of NK cells on colon cancer cell lines HT-29 and Lo Vo increased with the increase of E: T,reached the peak when e: t was 10:1,continued to increase the concentration of NK cells,and the killing effect decreased.The killing effect of NK cells combined with nivolumab on colon cancer cell line Caco-2 was higher than that of single NK cells and nivolumab only when e: t was 1:1,2:1 and 5:1.For the other two cell lines,nivolumab could not enhance the killing effect of NK cells in each e: t condition.3.NK cells have different killing efficiency to colon cancer cell lines Caco-2and HT-29,Caco-2 and Lo Vo,but there is no difference to HT-29 and Lo Vo.Results:1.The proportion of NK cells detected by flow cytometry expanded from 0days(7.23% ± 2.60%)to 14 days(81.01% ± 11.30%).2.The killing effect of NK cells on colon cancer cell line Caco-2 decreased with the increase of effect target ratio(E: T);The killing effect of NK cells on colon cancer cell lines HT-29 and Lo Vo increased with the increase of E: T,reached the peak when e: t was 10:1,continued to increase the concentration of NK cells,and the killing effect decreased.The killing effect of NK cells combined with nivolumab on colon cancer cell line Caco-2 was higher than that of single NK cells and nivolumab only when e: t was 1:1,2:1 and 5:1.For the other two cell lines,nivolumab could not enhance the killing effect of NK cells in each e: t condition.3.NK cells have different killing efficiency to colon cancer cell lines Caco-2and HT-29,Caco-2 and Lo Vo,but there is no difference to HT-29 and Lo Vo.Conclusion:1.Using a variety of cytokine induction and amplification methods,the harvested NK cells have high activity,good purity and can reach the therapeutic dosage.2.NK cells have strong killing activity on colon cancer cell line,and nivolumab can enhance the killing effect of NK cells on colon cancer cell line Caco-2.3.For these three colon cancer cell lines,the killing efficiency of NK cells is not related to the degree of differentiation.