Assessment of Immune Activation and Tolerance in Celiac Disease During Gluten Challenge

Inclusion Criteria: 1. Be a non-smoker who has not used tobacco- or nicotine-containing products (example, nicotine patch) for at least 6 months before Day 1 gluten administration. 2. Have well-controlled biopsy-proven CeD, compliant with a gluten-free diet (GFD) for greater than or equal to (\>=) 6 months preceding screening, with resolution of CeD symptoms, normalization of CeD serology, and in the judgment of the investigator, have inactive or minimally-active disease. 3. Be HLA-DQ2.5 and/or HLA-DQ8 positive, assessed at screening. If participants have already been genotyped, results from previous testing may be used in lieu of genotyping at screening. 4. Be willing to delay a planned procedure involving the use of powerful electromagnetic fields (example, magnetic resonance imaging), until the PillCam SB 3 capsule is excreted. 5. Not undergo VCE or optical coherence tomography (OCT) if has an implanted electromedical device or a swallowing disorder. 6. Not undergo OCT if has a contraindication to the device or procedure as per reference information. Exclusion Criteria: 1. Had major surgery and/or donated or lost 1 unit of blood (approximately 500 milliliter \[mL\]) within 8 weeks before the first dose of gluten. 2. Are unable to refrain from or anticipate the use of any unapproved medication, including prescription drugs, nonprescription drugs, and herbal remedies, beginning approximately 7 days before administration of the initial dose of gluten and continuing throughout the trial until the follow-up visit. 3. Consume excessive amounts of coffee, tea, cola, energy drinks, or other caffeinated beverages per day. An excessive amount is defined as greater than 6 servings (1 serving is approximately equivalent to 120 mg of caffeine). 4. Have positive IgA anti-tissue transglutaminase (tTG), IgA anti-deamidated gliadin peptide (DGP), and IgG DGP serologies at Screening. 5. Have inflammatory gastrointestinal disorders or autoimmune diseases other than CeD or autoimmune thyroid disease. 6. Have known or suspected gastrointestinal obstructions, strictures, or fistulas based on the clinical picture or pre-procedure testing and profile of the PillCam SB 3 capsule. 7. Endoscopy and intestinal biopsy are contraindicated.