[The vaccinal process after the peroral immunization of lambs with the Salmonella typhimurium 274 strain]

After oral immunization of lambs with S. typhimurium vaccine strain 274 these bacteria were characterized by low adhesion to the epithelial surface of the ileum, cecum, and colon, by very insignificant invasion into intestinal epithelium and then into lamina propria of the intestinal mucosa, mesenteric lymph nodes and the blood; the blood stream carried these bacteria further to the liver, spleen and other organs. Bacteria of strain 274 produced no damages, did not multiply and only persisted for 7-13 days in some lambs. No inflammation developed in response to oral immunization of the animals. The developing immunomorphological reaction presented as just a negligible increase in lymphocyte count in the intestinal epithelium, blast transformation and plasmatization in lymphatic follicles of Peyer's patches, hyperplastic mesenteric lymph nodes, blast and lymphocyte recirculation, moderate hyperplasia of white splenic pulp and insignificant lymphoid infiltration of portal interlayers of the liver.