Journal Article

Neutralization of Interleukin-9 Decreasing Mast Cells nfiltration in Experimental Autoimmune Encephalomyelitis

Jun-Jie Yin Xue-Qiang Hu Zhi-Feng Mao Jian Bao Wei Qiu Zheng-QiLu Hao-Tian Wu Xiao-Nan Zhong

2017

Overview

Background： Th9 cells are a newly discovered CD4＋ T helper cell subtype, characterized by high interleukin （IL）-9 secretion. Growing evidences suggest that Th9 cells are involved in the pathogenic mechanism of multiple sclerosis （MS）. Mast cells are multifunctional innate imnmne cells, which are perhaps best known for their role as dominant effector cells in allergies and asthma. Several lines of evidence point to an important role lbr mast cells in MS and its animal models. Simultaneously, there is dynamic ＂＇cross-talk＂ between Th9 and mast cells. The aim of the present study was to examine the IL-9-mast cell axis in experimental autoimmune encephalomyelitis （EAE） and deternaine its interaction alter neutralizing anti-lL-9 antibody treatment. Methods： Female C57BL/6 mice were randomly divided into three groups （#1 = 5 in each group）： mice with myelin oligodendrocyte glycoprotein （MOG）-induced EAE （EAE group）, EAE mice treated with anti-lL-9 antibody （anti-lL-9 Abs group）, and EAE mice treated with IgG isotype control （lgG group）. EAE clinical score was evaluated. Mast cells from central nervous system （CNS） were detected by flow cytometry. The production of chemokine recruiting mast cells in the CNS was explored by reverse transcription-polymerase chain reaction （RT-PCR）. In mice with MOG-induced EAE, the expression of IL-9 receptor （IL-9R） complexes in CNS and spleen mast cells was also explored by RT-PCR, and then was repeating validated by immunocytochemistry. In vitro, spleen cells from EAE mice were cultured with anti-lL-9 antibody, and quantity of mast cells was counted by flow cytoinetry alter co-culture. Results： Compared with IgG group, IL-9 blockade delayed clinical disease onset and ameliorated EAE severity （t = -2.217, P- 0.031 ）, accompany with mast cells infiltration decreases （day 5： t = -8.005, P 〈 0.001; day 15： t = -11.857, P 〈 0.001; day 20： t- 5.243, P = 0.001 ） in anti-lL-9 Abs group. The messenger RNA expressions of C-C motif chemokine ligand 5 （t = -5.932, P = 0.003） and vascular cell adhesion molecule-I （t = -4.029, P 0.004） were significantly decreased alter 1L-9 neutralization in anti-lL-9 Abs group, compared with lgG group. In MOG-induced EAE, the 1L-9R complexes were expressed in CNS and spleen mast cells. 1#7 vitro, splenocyles cultured with anti-lL-9 antibody showed significantly lower levels of mast cells in a dose-dependent manner, compared with splenocytes cultured with anti-mouse lgG （5 μg/ml： t = -0.894, P = 0.397; 10 p-g/ml： t = -3.348, P - 0.019：20 μg/ml： I - -7.639, P 〈 0.001 ）.Conclusions： This study revealed that 1L-9 neutralization reduced mast cell infiltration in CNS and ameliorated EAE, which might be relate to the interaction between IL-9 and mast cells.