Prediction of molecular mimicry between proteins from Trypanosoma sp. and human antigens associated with systemic lupus erythematosus.

The immune response against pathogens induces protection from future infection, however, molecular mimicry between the pathogen and the human host can promote autoreactive responses. Using in silico approaches, we identified molecular mimicry between Trypanosoma sp. and human autoantigens involved in the development of systemic lupus erythematosus (SLE). We retrieved all reported autoantigen amino acid sequences for SLE from the AAgAtlas database to perform PSI-BLAST against the Trypanosoma sp proteome to determine amino acid sequence identity with each other. The antigens given in the Protein Data Bank without a 3D structure were modeled by homology with the "Swiss Modeller Server". Epitopes shared between Trypanosoma sp. and human antigens were identified using the Ellipro server and the Immune Epitope Database (IEDB), and cross-reactive epitopes were assigned to the 3D models. 36 autoantigens involved in SLE showed molecular mimicry with Trypanosoma sp. Antigens Epitope prediction revealed that some autoantigens shared several antigenic.

Prediction of molecular mimicry between antigens from Leishmania sp. and human: Implications for autoimmune response in systemic lupus erythematosus.

Pathogens and humans share an intrinsic relation related to molecular mimicry in their antigens. Interactions between immune system and pathogenic antigens result in a production of antibodies that could protect against infection, but develop autoreactive responses mediated by autoantibodies that react to pathogenic and human antigens because they share epitopes. In this study, a pipeline of bioinformatic tools was used to explore the repertory of autoantigens implicated in the develop of Systemic Lupus Erythematosus and their homologous in Leishmania sp. With this, we screened and selected 33 molecular mimicry candidates. In 17 autoantigens from lupus was possible to perform epitope prediction and was found that, at least one potential cross epitope. Some of autoantigens with molecular mimicry were Aquaporin 4, nuclear autoantigens such as: Ubiquitin-related modifier 1 and Small nuclear ribonucleoprotein Sm. Also, mitochondrial, and ribosomal autoantigens were found to share molecular mimicry with antigens from Leishmania sp. In conclusion, this is the first study that provide evidence of molecular mimicry between antigens from Leishmania sp. and human. Implications for the develop of SLE and clinical manifestation deserve more study.