Inclusion Criteria:

• Male or nonpregnant female.
• 18 to 70 years old, inclusive, at Screening Visit.
• Biopsy-confirmed CD (intestinal histology showing villous atrophy).
• Positive for human leukocyte antigen (HLA)-DQ2 or HLA-DQ2/DQ8 - results will be obtained at Screening if unknown or results are not available. 
• Self-reported to be on a GFD for at least 6 months prior to Screening and agree to continue GFD throughout study, with the exception of the oral gluten challenge. 
• Normal or negative celiac serology, at screening, defined as: 1. Measurable total
• serum immunoglobulin A (IgA) AND 2. Negative or weak positive tissue transglutaminase (tTG) IgA titer OR 3. If IgA deficient, defined by a serum IgA level of < 3 mg/dL, negative or weak positive DGP- IgG titer.
• Vh:Cd ≥ 1.5 on screening biopsy.

 Exclusion Criteria:

• Positive for only HLA-DQ8.
• History of clinically confirmed immunoglobulin E (IgE)-mediated reaction and/or anaphylaxis to wheat (i.e., "wheat allergy"), barley or rye.
• Uncontrolled CD and/or active signs/symptoms of CD, in the opinion of the investigator.
• Untreated or active gastrointestinal disease such as peptic ulcer disease, esophagitis (Los Angeles Classification ≥ Grade C), irritable bowel syndrome, inflammatory bowel disease, or microscopic colitis. 
• Immunocompromised individuals, including those receiving immunosuppressive doses of corticosteroids (more than 20 mg of prednisone given daily or on alternative days for 2 weeks or more within 6 months prior Dose 1, any dose of corticosteroids within 30 days of Day 1, or high dose inhaled corticosteroids [> 960 µg/day of beclomethasone dipropionate or equivalent]) or other immunosuppressive agents.
• Presence or history of celiac-associated thyroid disease or Type 1 diabetes, regardless of current treatment.