ARS | Publication request: THE ACUTE PHASE RESPONSE OF ESCHERICHIA COLI CHALLENGED PIGS EXHIBITING A FEBRILE RESPONSE IN ABSENCE OF ELEVATED TNF-ALPHA

Submitted to: Journal of Animal and Veterinary Advances
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 9, 2004
Publication Date: N/A

Interpretive Summary: A study was conducted to evaluate the immune response when pigs were challenged with Escherichia coli. Pigs were given an oral dose of E. coli and thereafter blood samples were collected. Blood work conducted revealed concentrations of many hormones increased after E. coli administration and relationships existed between concentrations of these hormones and fever in the pigs. These data provide insight to interactions between the immune and endocrine systems, and that there is complex regulation of the fever response. Additionally, these data provide further clarification and novel insight of the fever response. These data will be used by immunologists and stress physiologists to enhance understanding of the fever response, and may, therefore, be used to help decrease the negative effects of sickness behaviors.

Technical Abstract: Escherichia coli causes gastrointestinal disease in many species; however, the associated immune response has not been well defined. To address this issue, twenty-two crossbred pigs were assigned to blood collection (n=10) or rectal temperature measurement (n=12) groups. Blood collection pigs were non-surgically cannulated one day prior to blood collection. At 0 h, all pigs received a 10 mL oral dose of 240 million colony-forming units of E. coli K88 via a nasogastric tube. Blood collection and rectal temperature monitoring occurred hourly from -1 to 5 h, every 30 minutes from 5 to 8 h, and at 24 h post-E. coli. Serum concentrations of cortisol (CS), interferon-gamma (IFN), tumor necrosis factor-alpha (TNF), interleukin-1beta (IL-1), IL-4, IL-6, IL-8, IL-10, serum amyloid A (SAA), C-reactive protein (CRP), haptoglobin (HG), and lipopolysaccharide (LPS) increased (P < 0.0007) after E. coli administration. Serum concentrations of IL-4 and IL-8 did not change and serum concentrations of TNF were undetectable. While TNF was not associated with increased rectal temperature, positive correlations existed between rectal temperature and CS (r = 0.49; P < 0.0001), IFN (r = 0.29; P < 0.0009), IL-1 (r = 0.45; 0.0001), IL-6 (r = 0.31; P < 0.0003), IL-10 (r = 0.35; P < 0.0001), and LPS (r = 0.29; P < 0.0009). These data indicate that circulating TNF does not play an integral role in the febrile response in pigs challenged with E. coli; however, CS, IL-1, IL-6, IL-10, and IFN may play an important role in initiating and controlling fever.