Immunoproteomic identification of antigenic candidate Campylobacter jejuni and human peripheral nerve proteins involved in Guillain-Barré syndrome.

Immunoproteomics is become a potent methodology used for identifying immunoreactive proteins. In this study, an immunoproteomic approach based on 2-dimensional gel electrophoresis (2D-PAGE) and immunoblotting combined with high resolution mass spectrometry (MS) was used to identify immunoreactive proteins that might be involved in mechanisms of Guillain-Barré syndrome (GBS) development, regardless of their potential reciprocal molecular mimicry. Proteins isolated from C. jejuni and human peripheral nerve tissue (HPN) were separated with 2D SDS-PAGE and subjected to western blotting using serum samples from GBS patients. The peptides generated after proteolysis of the immunoreactive proteins were submitted to nanoflow-high performance liquid chromatography-nano electrospray ionization coupled to high resolution mass spectrometry (nHPLC-nESI-MS and MS/MS) followed by SEQUESTdata analysis for proteins identification. In C. jejuni, immunoreactivity was found for GroEL and DnaK, structural proteins (MOMP), key enzymatic proteins necessary for the microbial proliferation (adenylate kinase, enolase, inorganic pyrophosphatase and aspartate ammonia-lyase), and antioxidant enzymes (alkyl hydroperoxide reductase-AhpC and DNA protection during starvation protein - DNA protection factor against Fe2+-mediated oxidative stress). HPN immunoreactive proteins identified were heat shock proteins (HSP), intermediate filaments (vimentin and desmin), and other proteins and enzymes such as troponin/tropomyosin complex and ATP synthase subunit beta and the keratan sulfate proteoglycan lumican. The targeting of vimentin and desmin, suggested that the neuronal autoimmune damage is specifically directed to intermediate neuronal (vimentin) and neuromuscular IF, probably localized nearby cell surface, affording increased accessibility to autoantibodies. These findings suggest that the post-infectious development of GBS may be also associated to additional concomitant immune factors that lead to nerve damage generated by auto-immune trigger(s) different from molecular mimicry.

Guillain Barré syndrome (GBS): new insights in the molecular mimicry between C. jejuni and human peripheral nerve (HPN) proteins.

Profile and immunoreactivity of proteins from HPN tissue, and from Campylobacter jejuni (O:19) were investigated. Proteins were extracted, separated by SDS-PAGE, their cross reactivity monitored by Western blotting, and identified by nHPLC-nESI-HRMS analysis. Proteins from C. jejuni, at Mw ~70 KDa were chaperone/co-chaperone proteins (GroEL, DnaK and HtpG). In the corresponding HPN band were serum albumin, neurofilament light peptide, cytoskeletal keratins and one HSP 70 and one HSP60. These chaperones reciprocally share high primary sequence homology and conservation of their known epitopes. These findings suggest that HSP chaperones may be suitable candidates involved in the molecular mimicry triggering GBS.