engleski

The effect of levamisole on gut mucosa of weaned pigs vaccinated against colibacillosis

Apart from its anthelmintic activity in domestic food animals , levamisole my be used as an adjuvant for preventive vaccines but information on its potentialadjuvant activity in hosts vaccinated agains gastrointestinal pathogenes is generally lacking.In the present study we aimed to test whether levamisole acts in weaned pigs vaccinated against colibacillosis by priming the lymphocytes in the gut mucosa.Ten weanwd piglets were used and alllocated into 2 equal groups.The experimental group was intramusculary primed with levamisole in immunostimulatzory dose of 2, 5 mg/kg given daily in 3 consecutive days-and the control group received saline accordingto the same schedule.Both groups werw orally vaccinated with the vaccinal Escherichia coli strain on day 0.Seven days later all pigs were infected with the virulent E.coli strain and sacrificed on post challenge day 6.Histological examination of the gut mucosa did not reveal significant morphological changes in the control.However , in the vaccinated weaned pigs primed by levamisole jejunal villi were shortened and their lamina propria was infiltrated with mononuclear cells.In the latter pigs, jejunal submucosa was oedematous but hyperplasia of the crypts was not generally observed.The immunohistocemical in situ staining results showed that priming by levamisole of the vaccinated weaned pigs selectively recruits andactivates T-cells in the villous epithelium as well as in the ileal Peyer's patch, a primary lymphoid organ generating B-lymphocytes.Our overall data suggest that levamisole apperaed to stimulate the effector sites of the gut immune system in the vaccinated weaned pigs, serving as a critical component in the establishment of protective immunity against enterotoxigenic E.coli-induced clinical disease.

Levamisol; weaned pigs; vaccination; Colibacillosis

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