Abstract
Peripheral blood lymphocytes of nine patients with active ulcerative colitis and eight normal individuals were cultured in the presence of E. coli O 14 and in the presence of homogenates of autologous rectal mucosa. After six days of incubation, the degree of blastoid transformation and mitosis was determined by phase contrast microscopy. Lymphocytes from both groups of patients reacted well in the presence of E. coli O 14 but did not react in the presence of rectal mucosa. These data suggest that both UC and normal lymphocytes are sensitized to E. coli O 14 but not to colonic mucosa, despite reported antigenic similarity between extracts of these two substances. The implications of these findings are discussed.