TI-LPMC were freshly isolated as described previously.24 (
link), 25 (
link) Briefly, after collection of biopsies from routine colonoscopy volunteers, tissues were treated with
HBSS (without CaCl
2, MgCl
2, MgSO
4; Gibco, Carlsbad, CA) and
EDTA (1 mM; Ambion, Grand Island, NY) to remove intraepithelial cells. LPMC were then isolated following enzymatic digestion of the biopsies with
Collagenase D (100 μg/mL; Roche, Indianapolis, IN) and
DNase I (10 μg/mL; Affymetrix, Cleveland, OH) and homogenization using the
Bullet Blender homogenizer (Next Advance Inc, Averill, NY). Cells were then washed and resuspended in complete medium (
RPMI 1640 [Gibco Invitrogen, Carlsbad, CA] supplemented with 10%
heat-inactivated fetal bovine serum [BioWhittaker, Walkersville, MD], 2 mM l-glutamine [HyClone, Logan, UT], 2.5 mM
sodium pyruvate [Gibco], and 10 mM
HEPES [Gibco], 100 U/mL
penicillin [Sigma-Aldrich, St. Louis, MO], 100 μg/mL
streptomycin [Sigma-Aldrich], and 50 μg/mL
gentamicin [Gibco]) and counted using Kova Glastic Slides (Hycor Biomedical, Garden Grove, CA). Cells were either stained immediately for immune-phenotyping by flow cytometry or stimulated overnight with
S Typhi–infected targets before staining (see later).
Booth J.S., Patil S.A., Ghazi L., Barnes R., Fraser C.M., Fasano A., Greenwald B.D, & Sztein M.B. (2017). Systemic and Terminal Ileum Mucosal Immunity Elicited by Oral Immunization With the Ty21a Typhoid Vaccine in Humans. Cellular and Molecular Gastroenterology and Hepatology, 4(3), 419-437.