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Conference abstract, 2004

Subsequent changes in leukocyte populations during the clinical and recovery phases of experimental swine dysentery

Andersson Märit, Johannisson Anders, Jonasson Robert, Jensen Waern Marianne, Jacobson Magdalena

Abstract

Swine dysentery (SD), with the gram-negative spirochete Brachyspira hyodysenteriae being the causative agent, is characterised by severe muco-haemorrhagic diarrhoea. The knowledge with regards to the systemic immune response to the acute infection and during the recovery is limited, but recent data indicate that the distribution of lymphocytes into subsets differ among pigs that resist the infection and those that develop SD. The present study was therefore aimed to further examine the levels of circulating leukocytes and lymphocyte subpopulations before, during and after experimentally induced SD. Ten healthy pigs (~23 kg) were fed a provocative diet before oral challenge with B. hyodysenteriae during 3 consecutive days. Clinical examinations were performed daily. Blood was sampled before challenge, 4 days after challenge, daily at 4 occasions during SD and at days 1, 3, 7, 11 and 15 of the recovery phase. Animals that remained healthy (n=2) were sampled once a week. Total and differential white blood cell counts were performed. Isolated leukocytes were double stained with CD4, CD8, CD8b, CD45RA, gd (Po-TcR1-N4) or CD21 primary antibodies followed by FITC- and PE-conjugated secondary antibodies. Thirty thousand cells/sample were characterised according to size, granularity and FITC/PE staining by flow cytometry. Eight animals developed SD with haemorrhagic diarrhoea after an average incubation period of 17 ±3 days. The average daily weight gain was 0.74 ±0.04 kg before SD, 0.05 ±0.12 kg during SD and 1.25 ±0.06 kg during recovery. The alterations in total number of blood neutrophils, monocytes, lymphocytes and subpopulations thereof are summarized in table 1. In conclusion, the number of neutrophils and monocytes appeared to increase at SD whereas B-lymphocytes (CD21+) and double positive T lymphocytes (CD4+CD8+) remained unaltered during SD and recovery. CD8+, CD8+CD4- and CD8+CD8b+ cells tended to increase as a response to challenge in all animals, which further strengthen the role of CD8+ cells during SD

Published in


Publisher: International Veterinary Immunology Symposium

Conference

7th International Veterinary Immunology Symposium