腹腔注射白细胞介素22抗体对猪螺杆菌感染后小鼠胃黏膜相关淋巴样组织形成的影响

The effect of interleukin-22 antibody intraperitoneal injection on the formation of gastric mucosa associated lymphoid tissue in mice after Helicobacter suis infection

目的研究腹腔注射白细胞介素（interleukin，IL）22抗体对猪螺杆菌（Helicobacter suis，H.suis）感染后小鼠胃黏膜相关淋巴样组织（mucosa associated lymphoid tissue，MALT）形成的影响及其可能的机制。方法40只雌性C57BL/6小鼠随机分为4组，每组10只，即正常对照组（normal control，NC组），H.suis感染组（HS组），抗体干预组（antibody treated，Ab组）与H.suis感染＋抗体干预组（HS＋Ab组）。Ab组与HS＋Ab组自感染后第2天开始给予50 μg小鼠IL-22单克隆抗体腹腔注射；NC组与HS组给予等量的同型对照抗体腹腔注射，每周1次，共12周后处死小鼠，取其胃组织行HE染色检测各组小鼠胃黏膜淋巴滤泡的数量与大小；分别采用实时荧光定量PCR（real-time PCR）与Western blot检测各组小鼠胃组织中IL-22与趋化因子CXCL （CXC-chemokine ligand）13的表达水平；体外培养人脾脏成纤维细胞株，加入IL-22在100 ng/mL的浓度下分别刺激24与48 h后分别检测细胞与培养液中CXCL13的表达水平；分离获得H.suis感染小鼠的胃组织免疫细胞，加入IL-22分别在50 ng/mL、100 ng/mL、200 ng/mL的浓度下刺激24 h，检测细胞与培养液中CXCL13的表达水平。结果H.suis感染可诱导小鼠胃黏膜滤泡的形成；与HS组相比，HS＋Ab组小鼠胃黏膜淋巴滤泡的数量明显减少且变小[（0.12±0.03）比（0.09±0.02）；（71.34±11.25）比（28.75±7.46）]，胃组织中IL-22与CXCL13的表达水平亦明显下降[（1.39±0.25）比（0.48±0.08）；（1.61±0.27）比（0.45±0.09）]。人脾脏成纤维细胞在体外经IL-22刺激后，其细胞中与培养液中CXCL13的表达水平均较未经刺激的相应对照组明显增加[（1.52±0.29）比（0.22±0.08）；（1.97±0.27）比（0.24±0.11）；（47.4±5.21）比（8.3±0.97）；（69.7±7.95）比（8.9±1.13）]，且刺激48 h后的CXCL13表达水平要显著高于刺激24 h后；小鼠胃组织免疫细胞在体外经不同浓度的IL-22刺激后，其细胞中与培养液中CXCL13的表达水平均较未经刺激的相应对照组明显增加[（4.83±0.67）比（0.98±0.23）；（6.35±0.86）比（1.03±0.21）；（8.84±1.12）比（1.07±0.25）；（25.31±3.61）比（4.33±0.62）；（41.33±5.18）比（4.47±0.58）；（58.35±6.26）比（4.54±0.65）]，且CXCL13表达水平随着IL-22刺激浓度的增加也相应增加。结论IL-22可能通过促进CXCL13的表达在H.suis感染后胃MALT的形成过程中发挥重要作用。

Objective To investigate the effect of interleukin-22 antibody intraperitoneal injection in the formation of gastric mucosa associated lymphoid tissue（MALT） in mice after Helicobacter suis infection and its possible mechanism.Methods Forty female C57BL/6 mice were randomly divided into four groups（10 mice per group）, which were named as normal control（NC） group, H.suis infection（HS） group, antibody treated（Ab） group and H.suis infection plus antibody treated（HS＋ Ab） group.The mice of Ab group and HS＋ Ab group were administrated with 50 μg mouse IL-22 Ab by intraperitoneal injection from the second day postinfection.The mice of NC group and HS group were administrated with the equal amount of isotype control Ab by intraperitoneal injection.The antibody treatment was given once a week and for 12 weeks.Mice were sacrificed to collect gastric tissues.The number and size of gastric lymphoid follicles were detected by HE staining and the expression levels of IL-22 and chemokine CXCL13 in the stomachs of mice were detected by real-time PCR and Western blotting respectively.Human spleen fibroblasts were cultured in vitro and stimulated by IL-22 under the concentration of 100 ng/mL for 24 h or 48 h. The expression levels of CXCL13 in the cells and culture medium were detected.The immune cells from gastric tissues in H.suis-infected mice were isolated and stimulated by IL-22 under the concentration of 50 ng/mL, 100 ng/mL and 200 ng/mL for 24 h. The expression levels of CXCL13 in the cells and culture medium were detected.Results H.suis infection induced the formation of lymphoid follicles in the gastric mucosa.The number and size of gastric lymphoid follicles and the expression levels of IL-22 and chemokine CXCL13 in the stomachs of HS＋ Ab group were significantly decreased compared with HS group.After IL-22 stimulation in vitro, the expression levels of CXCL13 in the spleen fibroblasts and culture medium were significantly increased compared with corresponding unstimulated group, which were higher after 48 h stimulation compared with 24 h stimulation.After stimulation of IL-22 under different concentrations, the expression levels of CXCL13 in the immune cells and culture medium were significantly increased compared with corresponding unstimulated group, which were upregulated along with the increased IL-22 concentation.Conclusion IL-22 may play an important role in the formation of gastric MALT after H.suis infection by upregulating the expression of CXCL13.