Characterization of myelin oligodendrocyte glycoprotein (MOG)35-55-specific CD8+ T cells in experimental autoimmune encephalomyelitis.

BACKGROUND: The pathogenesis of multiple sclerosis (MS) is mediated primarily by T cells, but most studies of MS and its animal model, experimental autoimmune encephalomyelitis (EAE), have focused on CD4 T cells. The aims of the current study were to determine the pathological interrelationship between CD4 and CD8 autoreactive T cells in MS/EAE. METHODS: Female C57BL/6 mice (n = 20) were induced by myelin oligodendrocyte glycoprotein (MOG)35-55 peptide. At 14 days after immunization, T cells were isolated from the spleen and purified as CD4 and CD8 T cells by using CD4 and CD8 isolation kits, and then the purity was determined by flow cytometric analysis. These cells were stimulated by MOG35-55 peptide and applied to proliferation assays. The interferon-gamma (IFN-γ) and interleukin (IL)-4 secretion of supernatant of cultured CD4 and CD8 T cells were measured by enzyme-linked immunosorbent assays (ELISA). For adoptive transfer, recipient mice were injected with MOG35-55-specific CD8 or CD4 T cells. EAE clinical course was measured by EAE score at 0-5 scale and spinal cord was examined by staining with hematoxylin and eosin and Luxol fast blue staining. RESULTS: CD8CD3 and CD4CD3 cells were 86% and 94% pure of total CD3 cells after CD8/CD4 bead enrichment, respectively. These cells were stimulated by MOG35-55 peptide and applied to proliferation assays. Although the CD8 T cells had a generally lower response to MOG35-55 than CD4 T cells, the response of CD8 T cells was not always dependent on CD4. CD8 T cell secreted less IFN-γ and IL-4 compared with CD4 T cells. EAE was induced in wildtype B6 naïve mice by adoptive transfer of MOG35-55-specific T cells from B6 active-induced EAE (aEAE) mice. A similar EAE score and slight inflammation and demyelination were found in naive B6 mice after transferring of CD8 T cells from immunized B6 mice compared with transfer of CD4 T cells. CONCLUSION: Our data suggest that CD8 autoreactive T cells in EAE have a lower encephalitogenic function but are unique and independent on pathogenic of EAE rather than their CD4 counterparts.

[Ammonia volatilization and nitrogen use efficiency in the field of fresh edible maize as affec-ted by different band fertilization depths of controlled-release urea]. / æŽ§é‡Šå°¿ç´ æ¡æ–½æ·±åº¦å¯¹é²œé£ŸçŽ‰ç±³ç”°é—´æ°¨æŒ¥å‘å’Œæ°®è‚¥åˆ©ç”¨çŽ‡çš„å½±å“.

A field experiment was conducted to examine the effects of controlled-release urea (CRU) application on ammonia (NH3) volatilization, nitrogen (N) use efficiency and fresh ear yield of fresh edible maize. The treatments included one control (CK: no N fertilizer application) and four different band fertilization depths (0, 5, 10, 15 and 20 cm). Results showed that NH3 volatilization from non-fertilization band and planting band mainly occurred in the first two weeks after the fertilization, which lasted for almost a month in the fertilization band. Compared to CK, surface broadcasted CRU (0 cm) significantly increased NH3 volatilization from wide-row non-fertilization band or planting band in field. Soil NH3 volatilization amounts ranged from 3.1 to 25.5 kg N·hm-2 with the different depths of CRU application treatments, accounting for 1.7%-14.2% of total N applied. The cumulative NH3 volatilizations were comparable among the depths of 10, 15 and 20 cm of CRU fertilization treatments, which were significantly decreased by 85.9%-87.8% and 67.0%-71.6% as compared with surface broadcasted CRU and 5 cm of CRU fertilization, respectively. The increases of CRU application depth within a certain extent could increase fresh ear yield, total nitrogen accumulation of plants during milking stage, partial factor productivity, agronomic efficiency and apparent recovery efficiency of nitrogenous fertilizer, and the maximum values of these indices were recorded for 15 cm depth. We concluded that CRU application at 15 cm depth would be the optimal practice in terms of reducing NH3 volatilization and improving N use efficiency of fresh edible maize.