[Effect of alloreactive natural killer cells on immune reconstitution in mouse haploidentical bone marrow...

The study was purposed to investigate the effect of alloreactive natural killer (alloNK) cells on immune reconstitution in murine haploidentical bone marrow transplantation (BMT). The murine model of haploidentical BMT was established by using (C57BL/6×BALB/c)BCF(1)(H-2(d/b)) mouse as the donor, and BALB/c (H-2(d)) mouse as the recipient. Recipient mice were divided into BMT group, non-allo-reactive NK (non-alloNK) cell group and alloNK cell group according to different transfusion. The effect of adding alloNK cells to transfusion was assessed by thymus pathology, the proportion of spleen NK cells, the spleen cell proliferation, the IFN-γ and IL-4 concentrations product at 24 and 48 h of recipient spleen cell culture supernatant at 2 months after BMT. The results showed that there were no obvious difference in thymus tissue among 3 groups under the optical microscope. The proportion of recipient spleen NK cells in non-alloNK group was significantly lower than that in BMT group (P < 0.05). There was no significant difference in proliferation of the recipient spleen cells among 3 groups at 2 months after BMT. The IFN-γ concentration product at 24 and 48 h of recipient spleen cell culture supernatant in alloNK group was significantly lower than that in other 2 groups at 2 months after BMT (P < 0.05). The IL-4 concentration in each group was not significantly different (P > 0.05). It is concluded that alloNK cells do not damage the thymus structure and may induce Th2 immune response in murine haploidentical BMT.