Lymphatic tissue of the intestinal tract of germfree and conventional rabbits.

The lymphatic tissue of ileum, sacculus rotundus and appendix was poorly developed without germinal centres in germfree rabbits; on the other hand, in conventional rabbits, the lymphatic tissue was abundant with numerous germinal centers. In germfree rabbits, the stroma of villi of the jejunum and ileum possessed low cellularity, in conventional rabbits, the villi were wide with rich cellularity. The basal position of lymphocytes was predominant in the villi of ileum of germfree rabbits, in conventional rabbits a high percentage of lymphocytes was in the apical position.

Digestive enzymes of the mucosa of the small intestine and trypsin and chymotrypsin proteolytic activity of the intestinal contents of germ-free, monocontaminated and conventional rabbits.

The activity of the membrane-bound enzymes of the microvillous zone of the entreocytes (maltase, sucrase, trehalase, lactase, cellobiase, alkaline phosphatase and leucylaminopeptidase) was studied in mucosal smears from the proximal jejunum, ileum, caecum and sigmoid flexure in a group of control (C) (8) and germ-free (GF) (7) rabbits. The trypsin and chymotrypsin activity of the contents of the ileum, caecum and sigmoid flexure was studied in 6 C, 5 GF and 5 monocontaminated (MC) rabbits. In summing up it can be stated that the individual membrane-bound enzymes have a different gradient in the various intestinal segments of C and GF rabbits and that they differ reciprocally in character.

Trypsin and chymotrypsin activity of the intestinal content in germfree, monoassociated and conventional rabbits.

Trypsin (T) and chymotrypsin (CHT) activities in luminal contents of the ileum, caecum and sigmoideum were followed in conventional (6 animals), monoassociated (5) and germfree (5) rabbits by pH-stat automatic titration using p-toluenesulphonyl-L-arginine methylester and acetyl-L-tyrosine ethylester as substrates. In conventional rabbits with complete microbial flora an aborally increasing decline of both proteolytic activities of luminal contents was determined (ileum T 198.2 - CHT 100.

The role of immune pig colostrum, serum and immunoglobulins IgG, IgM, and IgA, in local intestinal immunity against enterotoxic strain in Escherichia coli O55 in germfree piglets.

The protective effect of pig immune colostrum, serum and immunoglobulins IgG, IgM and IgA against the enterotoxic strain of Escherichia coli O55, was studied in newborn germfree piglets. This strain produced accumulation of fluid and dilatation of intestine when injected into the ligated ileal segment of germfree piglets, which is considered to be the typical effect of enterotoxins. Erosion of the intestinal epithelium and penetration of bacteria into the submucosa were also observed.