Dose-Ranging Study of the Efficacy and Safety of TAK-101 for Prevention of Gluten-Specific T Cell Activation in Participants With Celiac Disease on a Gluten-Free Diet

Inclusion Criteria: 1. Biopsy-confirmed CeD that is well-controlled, defined as mild or with no ongoing signs or symptoms felt to be related to active CeD and with immunoglobulin A (IgA) tissue transglutaminase (tTG) \<2 × upper limit of normal (ULN) and IgG deamidated gliadin peptide (DGP) \<3 × ULN. Note: Participants may be retested for IgA tTG and IgG DGP to meet eligibility criteria at the discretion of the investigator. Intermittent symptoms would not exclude participants from participation as long as symptoms are generally well controlled in the opinion of the investigator, and as long as symptoms are back to baseline for 2 weeks before the run-in gluten challenge. 2. Must be able to maintain a gluten-free diet (GFD) for ≥6 months. 3. Must be HLA-DQ2.5 and/or HLA-DQ8 positive during screening laboratory testing. Exclusion Criteria: 1. Has received any investigational compound within 12 weeks (84 days) or 5 half-lives, whichever is longer, before signing of the informed consent form (ICF). 2. Has received TAK-101 in a previous clinical study. 3. Has presence of other inflammatory gastrointestinal (GI) disorders or systemic autoimmune diseases, that either have the potential to cause persistent GI symptoms similar to CeD or are not well controlled without the use of excluded medications. * Examples of conditions that are exclusionary include: inflammatory bowel disease, eosinophilic gastroenteritis or colitis, and microscopic colitis requiring treatment in the 6 months before screening. * Examples of conditions that may be permissible after discussion with the medical monitor/or sponsor include: systemic autoimmune disease such as scleroderma, psoriatic or rheumatoid arthritis, lupus that is stable and without GI involvement, well controlled autoimmune thyroid disease, well controlled type 1 diabetes or proton pump inhibitor -responsive eosinophilic esophagitis in symptomatic and histologically confirmed remission. 4. Has known or suspected refractory CeD or ulcerative jejunitis. 5. Has known or suspected allergy to wheat, such as hypersensitivity and/or anaphylaxis including wheat-dependent-exercise induced anaphylaxis (WDEIA). If there is a possible history of urticaria, angioedema, or anaphylaxis to wheat, investigators should perform testing for wheat anti-Immunoglobulin (anti-IgE) antibodies or refer to an allergist for evaluation prior to enrollment to rule out any of these allergies. 6. Ongoing systemic immunosuppressant, systemic (oral or IV) corticosteroid treatment, or has received treatment with systemic immunosuppressants or corticosteroids in the 12 weeks before run-in gluten challenge. 7. Has known or suspected clinically significant liver disease or positive test result for hepatitis B or C. 8. Has intolerable symptoms after the run-in gluten challenge and is unwilling to undergo subsequent post treatment gluten challenges. 9. Has known allergy to or intolerance of TAK-101 or any of its ingredients or excipients. Also, any subject with a symptomatic allergic reaction that is confirmed by laboratory serology such as elevated tryptase levels following the administration of TAK-101 will be excluded from future dosing. 10. Has a current diagnosis of active malignancy or malignancy diagnosed in the 5 years prior to screening or is receiving ongoing treatment for malignancy.