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Intestinal absorption of colostral lymphoid cells was studied in 23 piglets of four sows and 17 lambs of ewes. From the colostrum and blood of the dams the lymphoid cells were isolated with Ficoll-Paque and labelled with technetium (Na99mTcO4). In the 7th hour after birth, 10 ml volume of the cell suspensions (piglets: 10(7) cells, lambs: 5 x 10(7) cells) were injected, following laparotomy, directly into the stomach or into the jejunum, or through a nasooesophageal tube. Cryostat sections of duodenum, jejunum and lymph node samples of animals were examined by autoradiography. It was found that lymphoid cells present in the colostrum of a piglet and lamb of their own mother were absorbed from the digestive tract and, via the lymphatic vessel, were transported to the mesenteric lypmph nodes. Electron microscopy revealed that absorption takes place intercellularly. Colostral cells of sows other than a piglet's own mother (allogeneic cells), the lymphoid cells isolated from the blood and heat-treated colostral lymphoid cells were not absorbed. The immunization of ewes and their lambs by tetanus anatoxin demonstrate, that the absorbed lymphoid cells remain immunologically active, and may transfer immune information to the lambs. |
