Background: The immunoglobulin (Ig) secretory component (SC) is the extracellular component of the polymeric Ig receptor (plgR) that is responsible for the transcytosis of newly synthesized IgA. In addition, the SC seems to play important roles in regulating eosinophil functions and in enhancing local immune responses. SC expression in HT-29 has been shown to increase in response to interferon-gamma, interleukin (IL) 4 and IL-1, but whether tumor necrosis factor (TNF) alpha affects SC expression is disputed.
Objective: Our aim was to study whether TNF-alpha can affect the expression of SC in Caco-2 cells.
Methods: We used immunocytochemistry, enzyme-linked immunosorbent assay, Western blot, and quantitative real-time polymerase chain reaction to test SC-positive cells, free SC in culture supernatants, plgR mRNA, and protein expression of SC.
Results: TNF-alpha dose-dependently increased SC-positive cells, free SC in culture supernatants, plgR mRNA, and protein expression of SC.