Data Availability StatementThe datasets used and/or analyzed during the current study are available from your corresponding author on reasonable request. splenocytes or isolated T cells with NK cells. Moreover, the phenotype, localization, and function differences between different NK cell subtypes were determined by circulation cytometry, immunofluorescence, and ex vivo co-culturation. Results In this study, we found that adoptive transfer of NK cells ameliorated EAMG symptoms by suppressing Tfh cells and germinal center B cells. Ex lover vivo studies indicated NK cells inhibited CD4+ T cells and Tfh cells by inducing the apoptosis of T cells. More importantly, NK cells could be divided into CXCR5- and CXCR5+ NK subtypes according to the expression of CXCR5 molecular. Compared with CXCR5- NK cells, which were mainly localized outside B cell zone, CXCR5+ NK were concentrated in the B cell Minoxidil (U-10858) zone and exhibited higher expression levels of IL-17 and ICOS, and lower expression level of CD27. Ex lover vivo studies indicated it was CXCR5- NK cells not CXCR5+ NK cells that suppressed CD4+ T cells and Tfh cells. Further analysis revealed that, compared Minoxidil (U-10858) with CXCR5- NK cells, CXCR5+ NK cells enhanced the ICOS expression of Tfh cells. Conclusions These findings highlight the different functions of CXCR5- NK cells and CXCR5+ NK cells. It was CXCR5- NK cells but not CXCR5+ NK cells that suppressed Tfh cells and inhibited the autoimmune response in EAMG models. test, one-way ANOVA, and Spearman correlation test, where a value of ?0.05 was deemed significant. Graphs were produced, and statistical analyses were performed using GraphPad Prism. Results NK cells ameliorate EAMG symptoms and reduce serum anti-AChR97-116 antibody levels and antibody affinities To test for the regulatory functions of NK cells in EAMG, splenic NK cells (5 106) from donor Minoxidil (U-10858) rats were isolated and transferred into recipient EAMG rats twice at the day before the first and second immunization, respectively. Compared with control rats, NK cell-treated rats experienced lower clinical scores (Fig. ?(Fig.1b),1b), associated with reductions of anti-AChR97C116 IgG2a antibody levels (Fig. ?(Fig.1c).1c). There was a trending but not statistically significant decrease of anti-AChR97C116 IgG antibody affinities in NK cell-treated group (= 0.09, Fig. ?Fig.1d).1d). However, we did not find any differences in the concentrations of anti-AChR97C116 IgG, IgG1, or IgG2b between those two groups (Fig. ?(Fig.1c).1c). Interestingly, transient body weight loss from days 20 to 28 post-immunization (p.i.) was observed in NK cell-treated group (Fig. ?(Fig.11a). Open in a separate windows Fig 1 NK cell ameliorated EAMG symptoms and reduced serum anti-AChR97C116 IgG2a antibodies levels. NK cells were adoptively transferred into EAMG rats twice at the day before the first and second immunization, respectively. The body weights (a) and clinical scores (b) of NK cell-treated rats (= 7) and PBS-treated rats (= 6) were recorded every other day after the first immunization. The rats were sacrificed at the 46th day post the first immunization, and the blood sera were collected. Rabbit Polyclonal to SAA4 Serum anti-AChR97C116 IgG, IgG1, IgG2a, and IgG2b antibody levels were determined by ELISA (c). Anti-AChR97C116 IgG antibody affinity was as determined by the thiocyanate method (d). Data were offered as mean SEM. Results were associates of two impartial experiments. Unpaired Students test Minoxidil (U-10858) was used. Arrows mean intervention occasions. * 0.05, * 0.01, *** 0.001 NK cell adoptive transfer reduces Tfh and germinal center B cells in EAMG Considering that recent reports illustrated regulatory functions of NK cells in humoral immune response [15, 16], we decided to further examine the potential functions of NK cells in the regulation of Tfh cells and germinal center B cells. Consistently, EAMG rats treated with NK cells exhibited lower percentages of Tfh cells and germinal center B cells compared to untreated rats (Fig. ?(Fig.2a,2a, b). A slight but statistically significant decrease of B cell percentages in the NK cell-treated group was also observed (Fig. ?(Fig.2c,2c, left). However, the percentages of memory B cells were not changed by NK cell treatment (Fig. ?(Fig.2c,2c, right). The previous study illustrated Tfh cells with different cytokine profiles could modulate the affinity and isotype.