Incidence Of EAE Research Articles

PDCB does not promote CNS autoimmunity in the context of genetic susceptibility but worsens its outcome

BackgroundPara-dichlorobenzene (PDCB) is an aromatic hydrocarbon contained in mothballs that is potentially neurotoxic. A potential pathogenic role of PDCB in MS pathogenesis has been suggested. MethodsTo determine the ability of chronic PDCB ingestion to induce CNS autoimmunity in a genetically susceptible mammalian species, naive myelin oligodendrocyte glycoprotein peptide (MOGp)35–55 T cell receptor (TCR) transgenic mice (2D2) on the C57Bl/6 background were orally gavaged once daily with corn oil control, 125 mg/kg PDCB, or 250 mg/kg PDCB for 45 days. The incidence of spontaneous EAE is increased in this mouse strain. ResultsBoth PDCB treatment groups showed the same spontaneous incidence of EAE, an earlier disease onset, and a slight decrease in survival for 125 mg/kg PDCB mice compared to control mice. We were unable to detect any PDCB, or its metabolites 2,5-dichlorophenol, 2,5-dicholormethylsulfide, and 2,5-dichloromethylsulfone in the brain and spinal cord of control mice. In contrast, PDCB was readily detectable in both compartments in mice who received PDCB via oral gavage, with concentrations being significantly higher in the brain (p < 0.01). Levels of the metabolites 2,5-dichlorophenol and 2,5-dichloromethylsulfone were also significantly higher in brains compared to spinal cords. ConclusionOur study refutes the hypothesis that PDCB or its metabolites trigger spontaneous T cell-mediated CNS autoimmunity in the setting of genetic susceptibility. A slight increase in mortality with PDCB exposure may be due systemic toxicity of hydrocarbons.

Autoimmune encephalitis: Single cell PCR analysis of the intrathecal plasma cell repertoire

of the B cell receptor. Methods: We immunized AIDKO mice with rhMOG and examined the incidence and severity of disease in AIDKO versus wild type mice. We also evaluated parameters of T cell activation in the periphery and the CNS as well as the generation of anti-MOG antibodies. Furthermore, MOG-specific IgG1 antibodies were transferred into AIDKO mice after immunization. EAE was also induced in AIDKO vs WT mice with MOG35-55 to evaluate the clinical disease. Results: AIDKO mice immunized with rhMOG exhibited reduced severity and incidence of EAE corresponding with a reduction in cytokine-producing CD4 T cells in the central nervous system, as well as reduced infiltration of the spinal cord by immune cells. However, transfer of pathogenic anti-MOG IgG1 antibodies recovered full disease in AIDKO mice. Conclusions: These results suggest that the secondary diversification of the B cell receptor is required for B cells to exert their full encephalitogenic potential in EAE, and possibly duringMS. Interestingly, AIDKO mice immunized with MOG35-55 suffer of more severe clinical symptoms compared to WT mice, suggesting that B cells play a differential role in B cell dependent or B cell independent forms of EAE.

Conditional DC depletion does not affect priming of encephalitogenic Th cells in EAE

EAE, an animal model for multiple sclerosis, is a Th17- and Th1-cell-mediated auto-immune disease, but the mechanisms leading to priming of encephalitogenic T cells in autoimmune neuroinflammation are poorly understood. To investigate the role of dendritic cells (DCs) in the initiation of autoimmune Th17- and Th1-cell responses and EAE, we used mice transgenic for a simian diphtheria toxin receptor (DTR) expressed under the control of the murine CD11c promoter (CD11c-DTR mice o nC57BL/6 background).EAE was induced by immunization with myelin oligodendrocyte glycoprotein (MOG) protein in CFA. DCs were depleted on the day before and 8 days after MOG immunization. The mean clinical EAE score was only mildly reduced in DC-depleted mice when DCs were ablated before EAE induction. The frequency of activated Th cells was not altered, and MOG-induced Th17 or Th1-cell responses were not altered, in the spleens of DC-depleted mice. Similar results were obtained if DCs were ablated the first 10 days after MOG immunization with repeated DC depletions. Unexpectedly, transient depletion of DCs did not affect priming or differentiation of MOG-induced Th17 and Th1-cell responses or the incidence of EAE. Thus, the mechanism of priming of Th cells in EAE remains to be elucidated.

TCR Affinity for Self-Ligands Influences the Development and Function of Encephalitogenic T Cells

The specificity and affinity of self-reactive T cells is likely to impact the development of autoimmune-disease causing T cells in the thymus as well as their function in the periphery. We identified a naturally occurring, low affinity variant of an MBP Ac1-11/I-Au specific TCR that is known to induce EAE. Thymocytes in mice carrying the transgenes for this low affinity TCR were poorly positively selected, as compared to their high affinity TCR expressing counterparts. Nonetheless, CD4 T cells bearing the low affinity TCR accumulated in the periphery of the mice. Unlike mice expressing the high affinity TCR, these mice very rarely developed disease. However, if endogenous TCR expression was eliminated by breeding to RAG1 deficient mice, 100% of the mice carrying either the high or the low affinity versions of the TCR developed EAE. Intriguingly, while the incidence of EAE increased, the age of onset of disease in both mice was identical. These data suggest disease onset occurs during a short window of mouse development.

Overexpression of glia maturation factor reinstates susceptibility to myelin oligodendrocyte glycoprotein-induced experimental autoimmune encephalomyelitis in glia maturation factor deficient mice

Glia maturation factor (GMF), a primarily CNS localized protein was discovered and characterized in our laboratory. We previously demonstrated that GMF is the upstream regulator for excessive production and release of proinflammatory cytokines/chemokines in brain cells leading to the destruction of oligodendrocytes, the myelin forming cells, and neurons. We also reported that mice lacking endogenous GMF (GMF-deficient, GMF-KO) were resistant to myelin oligodendrocyte glycoprotein peptide 35–55 (MOG35–55) induced EAE, since immunization induced only delayed EAE with diminished severity. In the present study we show that a replication-defective adenovirus-GMF construct caused expression of GMF in CNS of GMF-KO mice and reinstated MOG35–55 induced early and severe EAE. Our results show that MOG35–55 immunization caused only a muted EAE and inflammation/demyelination in mice lacking endogenous GMF. The diminished incidence of EAE in GMF-KO mice was consistent with the significantly reduced expressions of cytokines/chemokines. The muted severity of EAE in GMF-KO mice was restored to full blown levels upon reintroduction of GMF using an adeno-GMF-virus (Adv-GMF) vector. Consistent with the clinical findings, histological examination of the CNS of mice with EAE revealed profound differences between wild type (Wt), GMF-KO, and GMF-KO mice with re-introduced GMF (GMF-KO+Adv-GMF). Spinal cord sections from mice with EAE were analyzed for the infiltration of mononuclear cells (inflammation) and myelin loss (demyelination). In Wt mice, 40% of spinal cord quadrants were positive for demyelination and 45% of spinal cord quadrants were positive for inflammation at the peak of EAE. Drastically reduced infiltrates (15%) and demyelination (10%) were found in GMF-KO mice that developed reduced severity of EAE. Upon GMF reintroduction in GMF-KO mice, MOG35–55 immunization caused extensive monocytes infiltration (48%) and demyelination (46%), similar to that observed in the immunized Wt mice. The levels of cytokine/chemokine in the spinal cords of mice at three time points, corresponding to the onset, peak severity and recovery period of EAE, show a distinct pattern of very large increases in IFN-γ, TNF-α, GM-CSF and MCP-1 in Wt and GMF-KO+Adv-GMF mice compared to GMF-KO and GMF-KO+Adv-LacZ mice.

Mice lacking myeloperoxidase are more susceptible to experimental autoimmune encephalomyelitis

EAE is a demyelinating disease which serves as an animal model for multiple sclerosis (MS). Myeloperoxidase (MPO) has been implicated in MS through its presence in invading macrophages, and by association of a −463G/A promoter polymorphism with increased risk. Also, MPO at 17q23.1 is within a region identified in genome scans as a MS susceptibility locus. We here examine the incidence of EAE in MPO knockout (KO) mice. MPO is detected in invading macrophages in the CNS of wild-type mice, yet unexpectedly, MPO–KO mice have significantly increased incidence of EAE: Ninety percent of MPO–KO mice developed complete hind limb paralysis as compared to 33% of wildtype (WT) littermates ( P<0.0001). This is the first evidence that MPO plays a significant role in EAE, consistent with its postulated role in MS.

Linkage of severity of experimental allergic encephalomyelitis to the rat major histocompatibility locus.

The incidence of EAE is determined by Ir-EAE, a gene linked to the rat MHC. EAE severity can be assessed by quantitative clinical and pathologic measures. Using these measures, one can say that disease severity in LBNF1 is approximately one-tenth that in Lewis. Analysis of LBNF2, LBC, BNBC, and parental Lewis strain reveals that severity is primarily a function of dose of Lewis MHC alleles. Non-MHC genes have a small but discernable effect.

ADJUVANT-ANTIGEN RELATIONSHIPS IN THE PRODUCTION OF EXPERIMENTAL "ALLERGIC" ENCEPHALOMYELITIS IN THE GUINEA PIG

Quantitative relationships between the amounts of encephalitogenic neural tissue and mycobacterial adjuvant are presented for the guinea pig, for comparison with similar results obtained in the mouse and presented in an accompanying paper by Lee and Schneider (27). Definite threshold amounts of both neural encephalitogenic and mycobacterial adjuvant can be defined. With the proper amounts of each component, 100 per cent of guinea pigs can be made to develop EAE, 97 per cent dying of it, and over 50 per cent becoming paralyzed by the 12th day after challenge. With moderate amounts of encephalitogen the severity and incidence of EAE can be very great, but this encephalitogenic potential can be masked if large amounts of mycobacteria are employed. The mechanism of this masking effect by excess adjuvant is not known, but speculation centers upon the possibility of competition of antigens of the mycobacteria at the expense of those of the encephalitogen.