[1] Agcy Sci Technol & Res, Dept Med, Div Gastroenterol, Singapore 138648, Singapore
[2] Agcy Sci Technol & Res, Dept Microbiol & Immunol, Singapore 138648, Singapore
[3] Agcy Sci Technol & Res, Singapore Immunol Network, Singapore 138648, Singapore
[4] Stanford Univ, Sch Med, Inst Immun Transplantat & Infect, Stanford, CA 94305 USA
[5] Stanford Univ, Sch Med, Dept Chem, Stanford, CA 94305 USA
[6] Stanford Univ, Sch Med, Dept Chem Engn, Stanford, CA 94305 USA
[7] Stanford Univ, Sch Med, Howard Hughes Med Inst, Stanford, CA 94305 USA