Binding of IgG from CeD patients to Hwp1 peptides was inhibited by III gliadin peptides

Binding of IgG from CeD patients to Hwp1 peptides was inhibited by III gliadin peptides. Conclusions Humoral cross-reactivity between Hwp1 and gliadin was observed during CeD and CI. sequence alignment of Hwp1 and one member (Genbank: “type”:”entrez-protein”,”attrs”:”text”:”ACM41414.1″,”term_id”:”221855615″,”term_text”:”ACM41414.1″ACM41414.1) of the common wheat Triticium aestivum subsp. Macha, gliadin family. The rNtermHwp1 sequence is framed and the rHwp1T sequence is shown below the solid line. The known transglutaminase substrate sequence includes amino acids 41C197. The T-cell epitope of gliadin is shown in bold. Identity between the two sequences is shown in red. (B) Multiple amino acid sequence alignment of rNtermHwp1 and different T-cell gliadin epitopes. T-cell epitopes from different members of the -gliadin (1: DQ2-g-III; 2: DQ2-g-IV; 3: DQ2-g-V and -III plus; 4: g-1; 5C6: DQ2) and -gliadin (7C9: DQ2) family are homologous to Hwp1. Identity between rNtermHwp1 and -gliadins is shown in red. The clustalW2 program (http://www.ebi.ac.uk/Tools/clustalw2/index.html) was used for both alignments.(TIF) pone.0121776.s002.tif (6.8M) GUID:?3C8F610D-88B9-4394-8929-8300CA235884 S3 Fig: (A) Sequences of the 38 overlapping 20-mer peptides designed from GU/RH-II Hwp1 N-term with color code according to their design. Native peptide (red); peptides with a switch of glutamine to glutamic acid in order to mimic the enzymic conversion carried out by transglutaminase: all Q changed for E (blue), combinatory changes for one Q/E replacement (yellow). Gray represents peptides not synthesized. Overlaps are underlined in black. (B) Sequences of the 17C23-mer peptides designed from different forms of gliadin (N1, I, III) and non-relevant peptide (NR). Homology motifs between Hwp1 and gliadin are in bold (PQQPQ: 3 and 5 repeating motif, respectively, in -gliadin and Hwp1; YPQQPQ, PQQQ: common motifs in -gliadin and Hwp1; PQPQLPY: -gliadin motif having high sequence homology with the repeated sequence PQPDIPC in Hwp1).(TIF) pone.0121776.s003.tif (7.8M) GUID:?88A3AB69-F135-466F-8328-A4A11EBBFECC S1 Materials and Methods: (A) Description of Cloning, expression and purification of rNtermHwp1 (B) SDS-PAGE and western blotting (C) Peptide arrays. (DOCX) pone.0121776.s004.docx (22K) BMS-582949 hydrochloride GUID:?3780D203-BA93-49D6-B981-FD5975D61A18 Data Availability StatementAll relevant data are within the paper and its Supporting Information files. Abstract Objective The protein Hwp1, expressed on the pathogenic phase of infection (CI) may be a triggering factor for Celiac disease (CeD) onset. We investigated cross-immune reactivity between BMS-582949 hydrochloride CeD and CI. Methods Serum IgG levels against recombinant Hwp1 and serological markers of CeD were measured in 87 CeD patients, 41 CI patients, and 98 healthy controls (HC). IgA and IgG were also measured in 20 individuals from each of these groups using microchips sensitized with 38 peptides designed from the N-terminal of Hwp1. Results CI and CeD patients had higher levels of anti-Hwp1 (p=0.0005 and p=0.004) and anti-gliadin (p=0.002 and p=0.0009) antibodies than HC but there was no significant difference between CeD and CI patients. CeD and CI patients had higher levels of anti-transglutaminase BMS-582949 hydrochloride IgA than HC (p=0.0001 and p=0.0039). During CI, the increase in anti-Hwp1 paralleled the increase in anti-gliadin antibodies. Microchip analysis showed that CeD patients were more reactive against some Hwp1 peptides than CI patients, and that some deamidated peptides were more reactive than their native analogs. Binding of IgG from CeD patients to Hwp1 peptides was inhibited by III gliadin peptides. Conclusions Humoral cross-reactivity between Hwp1 and gliadin was observed during CeD and CI. Increased reactivity to Hwp1 deamidated peptide suggests that transglutaminase is involved in this interplay. These results support the hypothesis that CI may trigger CeD onset in genetically-susceptible individuals. Introduction Celiac disease (CeD), also known as gluten-sensitive enteropathy, is a complex disorder where genetically-susceptible individuals develop signs of malabsorption and extra-intestinal manifestations after ingestion.