The Action Mechanism Of γδT Cells In Developing EAE Model And Remitting After Administration Of Schistosome Egg Antigens

Objective:1. To compare the experimental autoimmune encephalomyelitis (EAE ) models induced by proteolipid protein (PLP) peptide 178-191 with by peptide 139-151 on the day of onset of the disease , the severity of clinical signs, histological features and the course of the disease.2. To determine the frequency of y8T cells in mice immunized by PLP178-191 and the change after administration of schistosome egg antigens (SEA.), and to find out the role for y6T cells in EAE.3. To determine the influence of actived y8T cells to the LNC of mice immunized by PLP 178-191 on the cytokine secretion.Methods:1. SJL/J mice were injected a mixture of PLP178-191 or PLP138-151 with complete Freund's adjuvant, and then injected Bordetella pertussis bacilli to make experimental autoimmune encephalomyelitis (EAE) models. Each mouse was scored according to its clinical severity daily. The sections of brain and spinal cord were respectively stained with luxol fast blue or hematoxylin and eosin for histological evaluation.2. The frequency of CD3+ T cells and T cells in intestine intraepithelial lymphocytes (iIEL) and lymph node cells (LNC) of mice, which were naive or immunized with PLP178-191 or with PLP 178-191 and SEA, were analyzed by flow cytometry.3. LNC of mice immunized with PLP178-191 alone or together with SEA were deal with solid-phase anti-yS antibody. After incubation for 48h, IFN- Y and IL-4 concentration were determined using ELISA kits.Results:1. When PLPi78-i9i was compared with PLPng-isi on making EAE on a equimolar basis, the onset time of the disease induced by PLPns-igi was earlier, but the severity and histological features were indistinguishable. The both peptides were inclined to effective to induce R-R EAE.2. The frequency of CDj+ cells in ilEL was represented equally in the three groups. y8T cells expressed as a percentage of CD^+ cells in ilEL were higher in SEA administration group compared to controls, but lower to PLPng.igi immunization group. The proportion of CDa+ cells of LNC in PLP178-191 immunization group and SEA administration group were obviously lower than control group, but the variation of yST cells in LNC was similar with that in ilEL.3. Upon activation with anti-y8 antibody, the concentration of IFN- Y in control-well and PLPi7g_i9i stimulated-well of PLPng-igi immunization group and the concentration of IL-4 in control-well and PLPng.^i+SEA stimulated-well of SEA administration group were higher than that of un-incubated-well.Conclusions:1. Compared to PLPi39_i5i, the morbidity of EAE induced by PLPng.i9i was equally high, and the course of disease also inclines to relapse-remitting form. Because the clinical and histological characters of models induced by each of the two epitopes resemble MS, they are both perfect for the research of MS .2. The increased frequency of y8T cells in ilEL and LNC of the EAE model in early period indicated that they were likely to be the initial source of y8T cells founded in the CNS. y8T cells may contribute to the pathogenesis of EAE. The administration of SEA can reduce the frequency of y8T cells, which may be one of the therapymechanisms of SEA on EAE.3. The stimulation of PLP178-191 can make actived γδT cells promote the secretion of Thl-type cytokine, and the administration of SEA can make it turn to Th2-type secretion. γδT cells were likely to be important in the differentiation of Th0 cells into Th1 cells or Th2 cells.