Transfer Of Escherichia Coli Antibodies From Sow To Piglet

Abstract

EARLIER experiments Thomlinson, 1970a, 1971a) showed that piglets may be hypersensitive to certain serotypes of Escherichia coli at birth, and that pregnant sows immunised with either hen egg albumin or E. coli extracts conferred hypersensitivity on their young whether or not they had received colostrum. Sensitisation of the piglets may have resulted from transfer of maternal antibody across the placental barrier, or from transfer of antigen leading to active immunisation of the piglets.The purpose of the following experiments was to determine whether antibodies could be detected in the serum of newborn colostrum-deprived piglets from immunised dams and to investigate the origin of these antibodies. MATERIALS AND METHODSAnimals. Pregnant Large-White sows were obtained from the same source as those used in previous experiments (Shreeve and Thomlinson, 1970a). Piglets were separated from their dams before they received colostrum; blood samples were obtained from the anterior vena cava immediately after birth.Active immunisation ofsows. Five pregnant sows were immunised with E. coli serotype 0138:K81(B) extract prepared by the method of Erskine, Sojka and Lloyd (1957). The immunisation procedure was similar to that employed in previous experiments (Shreeve and Thomlinson, 1971a) except that, in two of the sows, it was begun in the first third of pregnancy, about the 35th day. All five received an intravenous injection of 2 ml of the same E. coli extract within 2 hr before parturition; this caused mild symptoms of shock. Two sows were immunised by the injection of a heat-killed formolised suspension of E. coli 0138:K81(B) by the intravenous route. Cultures were prepared on nutrient agar in Roux flasks and incubated at 37°C for 48 hr. The organisms were suspended and washed three times in sterile isotonic saline and were then heated in a waterbath at 60°C for 1 hr. Formaldehyde was added to give a concentration of 0.2 per cent. Before use, the suspension was diluted in saline to an opacity equal to that of Brown's tube no. 1. Three courses of injections were given at intervals of 10 days; each consisted of four injections at 48-hr intervals and the dose was increased progressively from 2 ml in the first course to 5 ml in the last. The final injection was given 10 days before the expected date of parturition.Passive immunisation of sows. Antiserum prepared from blood collected from sows that had been immunised with E. coli 0138:K81(B) extract was stored at -30°C. The pooled antiserum had an " 0 " agglutinin titre of 20,480. Two sows were each given an intravenous injection of 150 ml antiserum either 24 or 48 hr before parturition. This injection caused mild signs of shock.Immunoglobulin was prepared by adding ammonium sulphate to the antiserum to give a concentration of 40 per cent. The mixture was held at 4°C for 18 hr and centrifuged at 4500 r.p.m. for 45 min. The precipitate was dissolved in a minimal amount of distilled water and dialysed at 4°C overnight against a large volume of distilled water. The dialysate ...