Human autoantibodies to diacyl-phosphatidylethanolamine recognize a specific set of discrete cytoplasmic domains

• Autor(a) principal: Laurino, CCFC
• Data de Publicação: 2006
• Outros Autores: Fritzler, M. J., Mortara, Renato Arruda [UNIFESP], Silva, N. P., Almeida, I. C., Andrade, LEC
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UNIFESP
• Texto Completo: http://repositorio.unifesp.br/handle/11600/28755; http://dx.doi.org/10.1111/j.1365-2249.2006.03024.x
• topic: autoantibodies; autoantigen; epitope analysis; cytoplasmic domains; phospholipids; GW bodies

The aim of this study was to characterize a novel human autoantibody-autoantigen system represented as cytoplasmic discrete speckles (CDS) in indirect immunofluorescence (IIF). A distinct CDS IIF pattern represented by 3-20 discrete speckles dispersed throughout the cytoplasm was identified among other cytoplasmic speckled IIF patterns. the cytoplasmic domains labelled by human anti-CDS-1 antibodies did not co-localize with endosome/lysosome markers EEA1 and LAMP-2, but showed partial co-localization with glycine-tryptophan bodies (GWB). CDS-1 sera did not react with several cellular extracts in immunoblotting and did not immunoprecipitate recombinant GW182 or EEA1 proteins. the typical CDS-1 IIF labelling pattern was abolished after delipidation of HEp-2 cells. Moreover, CDS-1 sera reacted strongly with a lipid component co-migrating with phosphatidylethanolamine (PE) in high performance thin-layer chromatography (HPTLC)-immunostaining of HEp-2 cell total lipid extracts. the CDS-1 major molecular targets were established by electrospray ionization-mass spectrometry (ESI-MS), HPTLC-immunostaining and chemiluminescent enzyme-linked immunosorbent assay as diacyl-PE species, containing preferentially a cis-C18 : 1 fatty acid chain at C-2 of the glycerol moiety, namely 1,2-cis-C18 : 1-PE and 1-C16 : 0-2-cis-C18 : 1-PE. the clinical association of CDS-1 sera included a variety of systemic and organ-specific autoimmune diseases but they were also observed in patients with no evidence of autoimmune disease.