INTESTINAL-ABSORPTION OF COLOSTRAL LYMPHOCYTES IN NEWBORN LAMBS AND THEIR ROLE IN THE DEVELOPMENT OF IMMUNE STATUS

Two model experiments were conducted to study the intestinal absorptio n of colostral lymphoid cells and the role of these cells in the devel opment of immune status in newborn lambs. In experiment I, 17 lambs of 14 Merino ewes were used. Suspensions of lymphoid cells separated fro m the colostrum (cell density: 5x10(6)/ml) and blood (3x10(6)/ml) were labelled with technetium ((NaTcO4)-Tc-99m) of 37 MBq/ml radioactive c oncentration. In three groups of lambs, 10-ml volumes of the cell susp ensions were injected directly into the duodenum after laparotomy, whi le in a fourth group (group Ia) the same volume was administered to th e animals through an oesophageal tube. The labelled cells revealed tha t colostral cells of the lamb's own dam are absorbed from the gastroin testinal tract and get into the newborn lamb's lymph circulation irres pective of the route of application. In experiment II, involving 40 la mbs of 40 ewes, we studied the effect of absorbed colostral lymphocyte s on the development of the newborn lamb's immune status. Twenty ewes (group A) each were treated with 3 ml tetanus anatoxin twice, while th e remaining animals (group B) were left uninoculated. Lambs of group A (designated A2) were separated from their dams immediately after birt h, then were administered, through an oesophageal tube, 10 ml of a sus pension of lymphoid cells (cell density: 5x10(6)/ml) separated from th e maternal colostrum. Subsequently, the lambs were interchanged with l ambs of nonimmunized ewes of group B (designated lambs B1), i.e. were mutually put out to nursing. At three days of age, lambs of groups A1, A2, B1 and B2 were inoculated with 3 ml tetanus anatoxin, then blood samples were taken from them 5 times in a period of 27 days for compar ative examination of the humoral and cellular immune reactions. The re sults demonstrate that lymphoid cells from the colostrum of the lambs' own dam become absorbed into the newborn lambs' lymph circulation, re main immunologically active and may transfer, besides immunological me mory, also cellular activity.