Immunity to Cholera: Antibody Response in the Lower Ileum of the Rabbit

Abstract

Extracts were prepared of whole tissue of the lower ileum, of cells separated by the citrate method, and of mucosal tissue of the muscularis after the removal of cells; all tissues were taken from rabbits immunized by parenteral and/or intraintestinal routes with cell-free supernatant of peptone-water cultures of Vibrio cholerae. Before preparation of extracts, the bowel section was washed with isotonic saline. The tissue and cell extracts, and wash, together with serum, were titrated for antitoxic and vibriocidal antibody. All showed the presence of antitoxic and complement-dependent vibriocidal antibody. Antibody activity was precipitated by 50% saturation with ammonium sulfate, and the recovery of precipitable protein was the same for all extracts, about 0.2 mg/cm of bowel. The antibody content ranged from 1,261 units of antitoxin/mg in tissue extract to 85 units/mg in wash. Antibody occurred in a concentration gradient from tissue to lumen, and vibriocidal antibody was more readily released from cells than was antitoxin. IgG and IgA, but not IgM, were found by immunoelectrophoresis to be present in extracts of tissues and cells and in wash.