Role of glucose in attachment of G. lamblia. (A) Trophozoites in medium containing 5 mM glucose were plated into 24-well tissue culture plates and incubated under anaerobic conditions, and levels of glucose remaining in the medium were measured after a 5-h incubation period. Glucose consumption is expressed as the mean + SEM percent relative to consumption of the parental cell line WB (n = 3 to 4 experiments). The average glucose consumption of WB cells was 21 nmol/106 cells/h. *, P < 0.05 (paired t test) relative to the parental cell line. (B) Attachment of G. lamblia WB to plastic tubes was assessed 1.5 h after incubation in RPMI medium containing cysteine, bile, fetal calf serum, and 5 mM glucose (Gluc) and/or 5 mM arginine (Arg). Data are means + SEM percentages of attached cells relative to total cells in the culture (n = 3 experiments). *, P < 0.05 (t test) relative to the percentage of attached cells in medium without glucose or added arginine (No Gluc).