Jiao Yu-Meng, Zhang Li, Ge Yi-Yue, Liang Yue-Jin, Yong Wang
Department of Pathogenic Biology, Nanjing Medical University, Nanjing 210029, China.
Zhongguo Xue Xi Chong Bing Fang Zhi Za Zhi. 2011 Jun;23(3):301-6.
To explore the effects of excreted/secreted antigens (ESA) of Toxoplasma gondii on CD4+CD25+ Foxp3+ T cells and NK cells of melanoma-bearing mice, as well as the tumor growth.
B16F10 (denoted B16) tumor cells were cultured in complete medium and maintained by serial passage in vitro. The 2x 10(5) B16 tumor cells were injected into the right flank of the mouse to establish the tumor-bearing mice model. Mice were randomly divided into four groups, namely PBS, B16F10, PES/ESA and B16F10/ESA groups after ESA injections. On days 2, 4 and 6 post-ESA injection, the spleens were removed. The percentage of CD4+CD25+ Foxp3+ T cells and NK cells in splenocytes were determined by flow cytometry; the suppression functions of CD4+CD25+ Tregs and the NK cell activity were detected by WST-8 and LDH methods, respectively. The tumor growth of each group was measured.
On Days 4 and 6 post-ESA injection, the percentages of CD4+CD25+ Foxp3+ T cells in splenocytes of the B16F10/ESA-injected mice decreased being (1.65 +/- 0.18)% and (1.56 +/- 0.17)%, respectively, and compared with those in the B16-injected mice [(2.47 +/- 0.10)% and (2.82 +/- 0.12)%], there were significant differences (both P values < 0.05). The inhibition of CD4+CD25+ Tregs of the B16F10/ESA-injected mice decreased markedly on Day 4 (50.03%) and Day 6 (50%) compared with those in the control (75.03% and 78.14%) post-ESA injection, there were significant difference (both P values < 0.05). The percentages of NK cells in splenocytes on Day 6 post-ESA injection [(3.58 +/- 0.07)%] was significantly higher than that of control [(2.61 +/- 0.13)%]. The activities of NK cells from B16F10/ESA - injected mice against B16 cells at different effect - to - target cell ratios (5 : 1, 10 :1, 20 : 1), increased significantly being 26.51%, 35.25%, 60.19%, respectively, while compared with those in the control (16.81%, 24.63% and 45.62%), there were significant differences (all P values < 0.05). In addition, the volume of the B16 tumors [(6 208.34 +/- 443.64)]mm3 was significantly smaller than that of control [(9 027.46 +/- 1 362.01)] mm3(P < 0.05) when measured at Day 35 post-tumor innoculation.
T. gondii ESA can downregulate CD4+CD25+Tregs while upregulating NK cells of B16 tumor-bearing mice quantitatively and functionally, therefore plays a role in suppression of tumor growth.
探讨弓形虫排泄/分泌抗原（ESA）对荷黑素瘤小鼠CD4+CD25+Foxp3+T细胞和自然杀伤细胞（NK细胞）以及肿瘤生长的影响。
将B16F10（简称B16）肿瘤细胞在完全培养基中培养并通过体外连续传代维持。将2×10⁵个B16肿瘤细胞注射到小鼠右腹侧以建立荷瘤小鼠模型。ESA注射后，小鼠随机分为四组，即PBS组、B16F10组、PES/ESA组和B16F10/ESA组。在ESA注射后第2、4和6天，取出脾脏。通过流式细胞术测定脾细胞中CD4+CD25+Foxp3+T细胞和NK细胞的百分比；分别采用WST-8法和LDH法检测CD4+CD25+调节性T细胞（Tregs）的抑制功能和NK细胞活性。测量每组的肿瘤生长情况。
ESA注射后第4天和第6天，注射B16F10/ESA小鼠脾细胞中CD4+CD25+Foxp3+T细胞百分比分别降至（1.65±0.18）%和（1.56±0.17）%，与注射B16小鼠的（2.47±0.10）%和（2.82±0.12）%相比，差异有统计学意义（P值均<0.05）。注射B16F10/ESA小鼠的CD4+CD25+Tregs抑制率在ESA注射后第4天（50.03%）和第6天（50%）较对照组（75.03%和78.14%）明显降低，差异有统计学意义（P值均<0.05）。ESA注射后第6天，脾细胞中NK细胞百分比[（3.58±0.07）%]显著高于对照组[（2.61±0.13）%]。注射B16F10/ESA小鼠的NK细胞在不同效靶比（5∶1、10∶1、20∶1）下对B16细胞的活性显著增加，分别为26.51%、35.25%、60.19%，与对照组（16.81%、24.63%和45.62%）相比，差异有统计学意义（P值均<0.05）。此外，在肿瘤接种后第35天测量时，B16肿瘤体积[（6 208.34±443.64）]mm³明显小于对照组[（9 027.46±1 362.01）]mm³（P<0.05）。
弓形虫ESA可下调荷B16肿瘤小鼠的CD4+CD25+Tregs，同时在数量和功能上上调NK细胞，从而发挥抑制肿瘤生长的作用。
