Suppression of growth of Vibrio cholerae in the intestine of immunized mice

In ligated intestinal loops of actively immunized adult mice, growth of V. cholerae 569B was suppressed approximately seven fold when compared to bacterial growth in non-immune animals. Similarly, growth of V. cholerae 569B was reduced in mice immunized with a hybrid vibrio strain, NCV569B-165, which shares only flagella antigens with V. cholerae 569B. Immunofluorescence studies of intestinal loop contents and intestinal sections indicated that, in non-immune mice, vibrios coated the intestinal mucosa. In contrast, the intestinal mucosa of immune animals was almost free of bacteria. The vibrios were found agglutinated in the intestinal lumen contents of immune animals. It was concluded that immunization suppressed the growth of V. cholerae in the intestinal lumen and the possibility that bacterial agglutination mediates this growth suppression is discussed.