Contributions
Abstract: P981
Type: Poster
Abstract Category: Pathology and pathogenesis of MS - MS and infections
Multiple Sclerosis (MS) is a neurodegenerative disease with an immune-mediated pathogenesis in which Epstein Barr Virus (EBV) is a risk factor. Our hypothesis is that EBV infection renders B cells potent antigen presenting cells (APC) for autoreactive T cells, through influences on intracellular proteolysis and post-translational modifications of self antigens. The aim of this study is to assess the effect of EBV infection in B cells on processing of myelin oligodendrocyte glycoprotein (MOG).
We investigated the processing of MOG through SDS PAGE gel analysis in the presence or absence of cathepsin inhibitors and we determined the proteolytic activity of Cathepsin G by activity assay. We also studied the effect of autophagy and citrullination on the processing of the immunodominant peptides MOG35-55 and MOG1-20. In addition, we measured the expression of peptidylarginine deiminase 2 (PAD2) by RT-PCR and LC3ii, an autophagy marker, by Western Blotting, in EBV infected and uninfected cells.
We found that EBV infection increases the activity of Cathepsin G, leading to increased degradation of MOG35-55 and MOG1-20 by B cells. However, infection also rescues recombinant extracellular human MOG from total degradation. Moreover, inhibition of Cathepsin G or citrullination of Arginine (Arg) in position 4 and 46 or increased autophagy activity abrogated the degradation of MOG peptides (destructive processing).
We propose a model in which EBV infection induces autophagy in B cells and a high concentration of Ca2+ in autophagosomes facilitates the activation of PAD, which mediates citrullination of Arg residues in putative F-LIR motifs (Arg4 and Arg46) that mediate association of rhMOG (peptides) with autophagosomes. Citrullinated MOG35-55 and MOG1-20 are protected from degradation and can be presented to autoreactive T cells on MHC. This mechanism could facilitate presentation of a disease-relevant myelin autoantigen that may be involved in MS induction and progression.
Disclosure: Elena Morandi: nothing to disclose
Anwar S Jagessar: nothing to disclose
Bert t`Hart: nothing to disclose
Bruno Gran: nothing to disclose
Abstract: P981
Type: Poster
Abstract Category: Pathology and pathogenesis of MS - MS and infections
Multiple Sclerosis (MS) is a neurodegenerative disease with an immune-mediated pathogenesis in which Epstein Barr Virus (EBV) is a risk factor. Our hypothesis is that EBV infection renders B cells potent antigen presenting cells (APC) for autoreactive T cells, through influences on intracellular proteolysis and post-translational modifications of self antigens. The aim of this study is to assess the effect of EBV infection in B cells on processing of myelin oligodendrocyte glycoprotein (MOG).
We investigated the processing of MOG through SDS PAGE gel analysis in the presence or absence of cathepsin inhibitors and we determined the proteolytic activity of Cathepsin G by activity assay. We also studied the effect of autophagy and citrullination on the processing of the immunodominant peptides MOG35-55 and MOG1-20. In addition, we measured the expression of peptidylarginine deiminase 2 (PAD2) by RT-PCR and LC3ii, an autophagy marker, by Western Blotting, in EBV infected and uninfected cells.
We found that EBV infection increases the activity of Cathepsin G, leading to increased degradation of MOG35-55 and MOG1-20 by B cells. However, infection also rescues recombinant extracellular human MOG from total degradation. Moreover, inhibition of Cathepsin G or citrullination of Arginine (Arg) in position 4 and 46 or increased autophagy activity abrogated the degradation of MOG peptides (destructive processing).
We propose a model in which EBV infection induces autophagy in B cells and a high concentration of Ca2+ in autophagosomes facilitates the activation of PAD, which mediates citrullination of Arg residues in putative F-LIR motifs (Arg4 and Arg46) that mediate association of rhMOG (peptides) with autophagosomes. Citrullinated MOG35-55 and MOG1-20 are protected from degradation and can be presented to autoreactive T cells on MHC. This mechanism could facilitate presentation of a disease-relevant myelin autoantigen that may be involved in MS induction and progression.
Disclosure: Elena Morandi: nothing to disclose
Anwar S Jagessar: nothing to disclose
Bert t`Hart: nothing to disclose
Bruno Gran: nothing to disclose