Effects of Yersinia enterocolitica infection on the development of the small intestine in newborn piglets : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Physiology at Massey University

A model of bacterial gastroenteritis has been developed in which the effects of Yersinia enterocolitica infection on the structural and biochemical development of the small intestine have been examined in neonatal piglets both during the infection period (3 and 5 days postinfection) and during the subsequent recovery period after antibiotic therapy (at 14 days). The potential of oral bovine lactoferrin and another bovine milk protein for preventing or reducing the effects of Y. enterocolitica gastroenteritis have been evaluated in these piglets. Newborn, colostrum-deprived piglets were inoculated orogastrically with a high dose (about 3 x 1010 colony forming units/ml) of Y. enterocolitica serotype 0:3, biotype 4. Diarrhoea began between 40 hours and 4 days after inoculation in 18 of the 19 animals and microabscesses, the typical lesions of Yersiniosis, were present in the mucosa of the small intestine in all infected piglets. At 5 days postinfection, microabscesses also were present in the liver of 7 of 8 piglets, and in the mucosa of the stomach in 2 animals. The mucosal damage and resulting malabsorption were reflected in the lower plasma glucose, Na+ and Cl- concentrations. Yersinia enterocolitica infection reduced the body weight but not body length, but did not significantly affect the gastrointestinal tract length or weight or the growth of non-intestinal organs except the liver. There were markedly lower lactase and sucrase, but not maltase and Na+-K+-ATPase, activities in the small intestine. The mucosal protein and DNA contents and the ratio of RNA to DNA in the small intestine were not significantly different in infected animals. Rapid proliferation of crypt cells resulted in crypt enlargement in the entire small intestine, but reduced vacuolation of the epithelium of the distal small intestine. Following institution of effective antibiotic therapy, gastrointestinal lesions were absent. Compared with controls, the piglets gained body weight at the same rate, although remaining lighter in weight, and organ weights and concentrations of plasma Na+ and Cl-, but not glucose, were no different. Previously-infected piglets retained an altered profile of disaccharidase activity with a lower lactase activity, higher maltase and sucrase activities and early appearance of sucrase activity in the ileum. There were fewer vacuoles in the epithelium of the distal ileum. A bovine milk fraction, but not bovine lactoferrin, appeared to reduce the severity of the infection due to Y. enterocolitica, there being shorter crypts, fewer proliferating crypt cells and higher lactase activity. The group means for the lesion number were also much lower although not significantly different. Oral supplementation with bovine lactoferrin in the milk formula did not have any beneficial effects in the infected piglets. In non-infected piglets, lactoferrin appeared to have trophic effects on the kidney and the small intestinal crypts, increased the lactase activity and caused an unexplained reduction in plasma glucose concentration and liver weight. Yersinia enterocolitica enteritis in newborn, colostrum-deprived piglets accelerated the maturation of the epithelium of the small intestine, indicated by reduced enterocyte vacuolation and an altered disaccharidase profile

Histo lesion scores 3.14 Dryad

Histology lesion scores. Data collected in field at post-mortem. Excel fil

Data from: Revaccination of cattle with Bacille Calmette-Guérin two years after first vaccination when immunity has waned, boosted protection against challenge with Mycobacterium bovis

In both humans and animals, controversy exists concerning the duration of protection induced by BCG vaccine against tuberculosis (TB) and whether revaccination enhances protection. A long-term study was undertaken to determine whether BCG-vaccinated calves would be protected against challenge with Mycobacterium bovis 2½ years after vaccination and to determine the effect of revaccination after 2 years. Seventy–nine calves were divided into five groups (n = 15–17 calves/group) with four of the groups vaccinated subcutaneously with 105 CFU of BCG Danish at 2–4 weeks of age and the fifth group serving as non-vaccinated controls. Three of the four BCG-vaccinated groups were revaccinated 2 years after the initial vaccination. One BCG-vaccinated group was revaccinated with BCG. A second group was vaccinated subcutaneously with a TB protein vaccine consisting of biopolyester particles (Biobeads) displaying two mycobacterial proteins, ESAT-6 and Antigen 85A, mixed with an adjuvant. A third group was vaccinated with TB proteins from M. bovis culture filtrate, mixed with an adjuvant. Twenty-three weeks after the BCG revaccination, all animals were challenged endotracheally with virulent M. bovis and a further 13 weeks later, animals were killed and necropsied to determine protection against TB. The BCG-vaccinated animals produced positive tuberculin caudal fold intradermal (15 of 62 animals) and IFN-γ TB test responses (six of 62 animals) at 6 months after vaccination, but not at subsequent time-points compared to the non-vaccinated animals. Calves receiving a single vaccination with BCG vaccine 2½ years prior to challenge were not protected against TB, while those revaccinated with BCG 2 years after the initial vaccination displayed significant reductions in lung and pulmonary lymph node lesion scores compared to the non-vaccinated animals. In contrast, no reduction in lesion scores was observed in the animals revaccinated with the TB protein vaccines with their immune responses biased towards induction of antibody

Revaccination of cattle with bacille Calmette-Guérin two years after first vaccination when immunity has waned, boosted protection against challenge with Mycobacterium bovis.

In both humans and animals, controversy exists concerning the duration of protection induced by BCG vaccine against tuberculosis (TB) and whether revaccination enhances protection. A long-term study was undertaken to determine whether BCG-vaccinated calves would be protected against challenge with Mycobacterium bovis 2½ years after vaccination and to determine the effect of revaccination after 2 years. Seventy-nine calves were divided into five groups (n = 15-17 calves/group) with four of the groups vaccinated subcutaneously with 105 CFU of BCG Danish at 2-4 weeks of age and the fifth group serving as non-vaccinated controls. Three of the four BCG-vaccinated groups were revaccinated 2 years after the initial vaccination. One BCG-vaccinated group was revaccinated with BCG. A second group was vaccinated subcutaneously with a TB protein vaccine consisting of biopolyester particles (Biobeads) displaying two mycobacterial proteins, ESAT-6 and Antigen 85A, mixed with an adjuvant. A third group was vaccinated with TB proteins from M. bovis culture filtrate, mixed with an adjuvant. Twenty-three weeks after the BCG revaccination, all animals were challenged endotracheally with virulent M. bovis and a further 13 weeks later, animals were killed and necropsied to determine protection against TB. The BCG-vaccinated animals produced positive tuberculin caudal fold intradermal (15 of 62 animals) and IFN-γ TB test responses (six of 62 animals) at 6 months after vaccination, but not at subsequent time-points compared to the non-vaccinated animals. Calves receiving a single vaccination with BCG vaccine 2½ years prior to challenge were not protected against TB, while those revaccinated with BCG 2 years after the initial vaccination displayed significant reductions in lung and pulmonary lymph node lesion scores compared to the non-vaccinated animals. In contrast, no reduction in lesion scores was observed in the animals revaccinated with the TB protein vaccines with their immune responses biased towards induction of antibody

Wallaceville IFN and CFT results Dryad

Skin test results collected in the field. Excel file. CFT= caudal fold test

IFN pgml results dryad

Interferon-gamma cytokine responses. Excel file from ELISA plate reader using Softmax-pro

Lesion table for bacto Dryad

Lesion table from histo scores. Samples collected at post-mortem. Excel fil

Summary of pathological and bacteriological findings following <i>Mycobacterium bovis</i> challenge.

<p>LN lymph node.</p><p>Non-vaccinated; BCG once, BCG-vaccinated, not revaccinated; BCG/BCG, BCG-vaccinated and revaccinated 2 years later with BCG; BCG/Biobeads, BCG-vaccinated and revaccinated 2 years later with TB biobeads displaying mycobacterial proteins, ESAT-6 and Ag85A; BCG/CFP, BCG-vaccinated and revaccinated 2 years later with <i>M. bovis</i> culture filtrate protein vaccine. Cattle were challenged with <i>M. bovis</i> 129 weeks after initial BCG vaccination and 23 weeks after revaccination. All animals were slaughtered and examined for TB lesions at 13 weeks after challenge. *Significantly different from the non-vaccinated group, <i>p</i><0.05.</p><p>Summary of pathological and bacteriological findings following <i>Mycobacterium bovis</i> challenge.</p

Antibody responses after revaccination and <i>Mycobacterium bovis</i> challenge.

<p>Antibody responses to <i>M. bovis</i> culture filtrate protein (A) and ESAT-6 peptides (B) were measured after revaccination and <i>M. bovis</i> challenge for the different vaccine groups. Non-vaccinated (•, n = 17); BCG-vaccinated, not revaccinated (○, BCG once group, n = 16); BCG-vaccinated and revaccinated 2 years later with BCG (▾, BCG/BCG group, n = 15); BCG-vaccinated and revaccinated 2 years later with TB biobeads displaying mycobacterial proteins, ESAT-6 and Ag85A (Δ, BCG/Biobeads group, n = 15), BCG-vaccinated and revaccinated 2 years later with <i>M. bovis</i> culture filtrate protein vaccine (▪, BCG/CFP group, n = 16). All animals were challenged with <i>M. bovis</i> at 23 weeks after revaccination (129 weeks after the initial BCG vaccination). Results expressed as a percentage of a strong positive control. Significantly different from the non-vaccinated group was denoted by ***p<0.001, **p<0.01, *p<0.05, with analysis undertaken on natural log-transformed data.</p