Abstract: Objective Explore the specificity and efficiency of YFP labeled natural killer cells through Vav-Cre induced YFP reporter system in mice. Methods We crossed ROSA26R-YFP and Vav-Cre mice and screened their YFP and Cre gene double positive progeny by genotyping. Then we analyzed the specificity of YFP in hematopoietic cells from immune organs including lymph nodes, spleen, thymus and bone marrow through flow cytometry. Next we analyzed the percentage of YFP positive cells in natural killer cells from lymph nodes, spleen and bone marrow. Results We obtained 11 double positive mice among 17 offsprings by crossing ROSA26R-YFP mice with Vav-Cre mice. The percentages of YFP positive cells in the immune organs including lymph nodes, spleen, thymus and bone marrow are 73.87%±1.51, 56.07%±1.47, 86.17%±1.74 and 53.60%±3.56, there are significant differences compared with the corresponding negative control cell（0.27%±0.01, 1.33%±0.91, 0.11%±0.01, 0.29%±0.03）,（P<0.01; double positive mice vs CTRL）; nevertheless in non-immune organ kidney, cells were almost YFP negative（double positive mice 0.72%±0.43 vs CTRL0.92%±0.27; P>0.05）. NK cells from lymph nodes, spleen and bone marrow of these double positive mice were 76.94%±0.84, 81.66%±1.18 and 88.92%±0.77 labeled by YFP (P<0.01; double positive mice vs CTRL). Conclusion YFP marked natural killer cells through Vav-Cre induced YFP reporter system in mice has strong specificity and high efficiency.

Key words: Cre recombinase, YFP reporter gene, natural killer cell, immune organ