Guillain-Barré syndrome-related Campylobacter jejuni in Bangladesh: ganglioside mimicry and cross-reactive antibodies

Abstract

Background: Campylobacter jejuni is the predominant antecedent infection in Guillain-Barré syndrome (GBS). Molecular mimicry and cross-reactive immune responses to C. jejuni lipo-oligosaccharides (LOS) precipitate the development of GBS, although this mechanism has not been established in patients from developing countries. We determined the carbohydrate mimicry between C. jejuni LOS and gangliosides, and the cross-reactive antibody response in patients with GBS in Bangladesh.

Methodology: Sera from 97 GBS patients, and 120 neurological and family controls were tested for antibody reactivity against LOS from C. jejuni isolates from GBS patients in Bangladesh (BD-07, BD-39, BD-10, BD-67 and BD-94) by enzyme-linked immunosorbent assay (ELISA). Cross-reactivity to LOS was determined by ELISA. The LOS outer core structures of C. jejuni strains associated with GBS/MFS were determined by mass spectrometry.

Principle findings: IgG antibodies to LOS from C. jejuni BD-07, BD-39, BD-10, and BD-67 IgG antibodies were found in serum from 56%, 58%, 14% and 15% of GBS patients respectively, as compared to very low frequency (<3%) in controls (p<0.001). Monoclonal antibodies specific for GM1 and GD1a reacted strongly with LOS from the C. jejuni strains (BD-07 and BD-39). Mass spectrometry analysis confirmed the presence of GM1 and GD1a carbohydrate mimics in the LOS from C. jejuni BD-07 and BD-39. Both BD-10 and BD-67 express the same LOS outer core, which appears to be a novel structure displaying GA2 and GD3 mimicry. Up to 90-100% of serum reactivity to gangliosides in two patients (DK-07 and DK-39) was inhibited by 50 µg/ml of LOS from the autologous C. jejuni isolates. However, patient DK-07 developed an anti-GD1a immune response while patient DK-39 developed an anti-GM1 immune response.

Conclusion: Carbohydrate mimicry between C. jejuni LOS and gangliosides, and cross-reactive serum antibody precipitate the majority of GBS cases in Bangladesh.

Figure 1. Serum samples from patients with GBS and from controls with other neurological disease (OND) and family controls (FC) were tested for IgG activity to lipo-oligosaccharides (LOS) from 6 C. jejuni.

Subcharts represent serum IgG activity to LOS from (A) C. jejuni BD-07 isolated from a GBS patient (B) C. jejuni BD-39 isolated from a GBS patient, (C) C. jejuni BD-10 isolated from a GBS/MFS patient, (D) C. jejuni BD-67 isolated from a GBS/MFS patient, (E) C. jejuni BD-94 isolated from a GBS patient (F) C. jejuni Penner HS:03 serostrain (CCUG 10937), lacking ganglioside mimics, as a control. *p<0.001. Lines () indicate cut-off value. GBS, Guillain-Barré syndrome; OND, other neurological disease; FC, family controls; LOS, lipo-oligosaccharides.

Figure 2. Binding of mouse monoclonal antibodies against LOS from C. jejuni BD-07 and BD-39.

DG-1 (binding to GM1), TBG-3 (binding to GD1a), EG-7 (binding to GD1b), EG-3 (binding to GQ1b) and EG-1 (binding to GQ1b/GT1a).

Figure 3. ELISA analysis of the cross-reactivity of GBS patient’s serum anti-ganglioside antibodies to LOS from the autologous C. jejuni strains.

A) Optical density (OD) of IgG anti-GD1a reactivity in serum from patient DK-07 by pre-incubation with LOS from the autologous C. jejuni BD-07 strain (GM1/GD1a mimic, Table 3) and from Penner HS:03 serostrain (CCUG 10937). B) Optical density (OD) of IgG anti-GM1 reactivity in serum from patient DK-39 by pre-incubation with LOS from the autologous C. jejuni BD-39 strain (GM1/GD1a mimic, Table 3) and from Penner HS:03 serostrain (CCUG 10937). Graphs represent data as mean ± standard error.

Figure 4. Proposed LOS outer core structures based on capillary-electrophoresis electrospray ionization mass spectrometry analysis of O-deacylated LOS samples (see Table S1).

(A) strains BD-07 and BD-39 show mimicry with GM1 and GD1a; (B) strains BD-10 and BD-67 show mimicry with GA2 and GD3. Terminal regions mimicking gangliosides are indicated with arrows.