Rotavirus stimulates IL-8 secretion from cultured epithelial cells

Abstract

Rotavirus is the most important cause of severe gastroenteritis in children worldwide. We have investigated cytokine responses to rotavirus infection of cultured intestinal epithelial cells. Interleukin 8 (IL-8) is a chemotactic and cell-activating cytokine that is synthesized by epithelial cells and induced in response to bacterial enteric pathogens. Rotavirus inoculation increased IL-8 mRNA levels in cultured intestinal epithelial cells within 2 hr of infection IL-8 secretion increased 102- to 103-fold by 8 hr postinfection. Secretion of TNFα or IL-1β, cytokines which themselves increase IL-8 secretion, was not induced by rotavirus, nor was that of TNFα, IFNα, IFNγ, or IL-6. Neutralizing antibodies to TNFα or IL-1α/β did not affect the IL-8 response. Secretion of IL-8 was dependent on an intact viral capsid, as single shell particles were inert. Neutralizing monoclonal antibodies (vp7-specific) that do not block cell attachment did block rotavirus stimulation of IL-8 secretion, indicating that attachment to the cell surface is not a sufficient stimulus to induce IL-8. Genetically inactivated rotavirus was also effective for IL-8 induction, indicating that viral replication was not required. These data suggest that epithelial cytokine IL-8 may be an important mediator of the host response to viral gastroenteritis pathogens such as rotavirus.