Cholera toxin and Salmonella typhimurium induce different cytokine profiles in the gastrointestinal tract

Salmonella infection of the gastrointestinal tract (GT) results in fluid secretion and inflammation. In contrast, cholera toxin (CT) induces fluid secretion but no inflammation. Using a murine ligated intestinal loop model, we investigated cytokine production (interleukin-1 [IL-1], IL-2, IL-4, IL-6, IL-10, gamma interferon, and tumor necrosis factor alpha) in the GT following exposure to these agents. Salmonella typhimurium induced a Th1-like cytokine profile in loops obtained from either nonimmune mice or Salmonella-immunized mice. CT induced only IL-6 and IL-10 production in ligated loops from nonimmune mice but induced a Th2-like cytokine profile in ligated loops obtained from CT-immunized mice. These results show that CT and S. typhimurium induce very different cytokine profiles in the GT.

Effect of prostaglandin E on immune function in normal healthy volunteers

Prostaglandin E (PGE) has been hypothesized to be the endogenous metabolite that results in the immunosuppression seen in patients with tumor and trauma. This has resulted in multiple investigators proposing that administration of PGE inhibitors, such as aspirin and indomethacin, might improve immune function in such patients. We administered a long acting PGE analog, misoprostol, to nine normal healthy volunteers for five days and assayed immune function before and after therapy. The PGE analog improved lymphocyte blastogenesis and increased tumor necrosis factor production. The PGE analog also resulted in the volunteers having symptoms similar to those seen in patients with sepsis. The results of these studies indicate that elevated levels of PGE do not seem to result in impairment of immune function, but may be the endogenous metabolite responsible for the symptologic factors seen in infected patients.