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Title: CYTOTOXICITY IN CHICKEN ALIMENTARY SECRETIONS AS MEASURED BY A DERIVATIVE OF THE TUMOR NECROSIS FACTOR ASSAY

Author
item Arnold, Judy
item Holt, Peter

Submitted to: Journal Of Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/21/1995
Publication Date: N/A
Citation: N/A

Interpretive Summary: The host immune response to enteric bacterial infections, including salmonellosis, results in inflammatory cells entering the intestine near the site of infection. These cells produce factors, such as cytokines, that are cytotoxic to bacteria-infected cells, resulting in loss of host cells. In this study we assess the cytotoxic activity in alimentary secretions from chickens in response to a Salmonella enteritidis (SE) infection. Secretions were collected and centrifuged. Activity was measured by the amount of cell damage or lysis caused by the secretions when added to chicken embryo fibroblasts. Cytotoxic activity of alimentary secretions from SE-infected hens was measured at intervals during the first 24 hours following infection and daily for the next ten days. The level of activity varied between hens but was maximal in secretions obtained at 24 hours and 10 days after SE infection. Maximal levels of cytotoxic activity in alimentary secretions from hens occurred in response to a dose of 500 million CFU/ml of SE. Withholding feed from hens affected this cytotoxic activity. The cytotoxicity in secretions from SE-exposed hens deprived of feed exceeded those of controls by five-fold.

Technical Abstract: The host immune response to enteric bacterial infections, including salmonellosis, results in inflammatory cells entering the intestine near the site of infection. These cells produce factors, such as cytokines, that are cytotoxic to bacteria-infected cells, resulting in loss of host cells. In this study an assay was developed, based on the tumor necrosis factor (TNF) assay, that measured the cytotoxic activity in alimentary secretions from chickens during a Salmonella enteritidis (SE) infection. Secretions were collected by pilocarpine-induced evacuation from the alimentary tract and clarified by centrifugation. Activity was assessed by the cytotoxic effect of secretions on chicken embryo fibroblasts as target cells. Cytotoxic activity from SE-infected hens was measured at intervals during the first 24 h following infection and daily for the next 10 d. The level of activity varied between hens but was maximal in secretions obtained at 24 h and 10 d after SE infection. Maximal levels of cytotoxic activity in alimentary secretions from hens occurred in response to a dose of 500 million cfu/mL of SE. The cytotoxicity in secretions from SE-exposed hens that were deprived of feed was greater than those from control SE-exposed hens by more than five-fold.