Supernatant from cultured intestinal cells inhibits the growth of gram-negative bacteria

Bacterial growth chambers of Transwell units bearing intestinal epithelial monolayers (C2BBe) was consistently observed to be stagnant during the course of transmigration studies with Salmonella typhi. This limitation could not be explained by varying the bacterial load in the inoculum. Conditioned media produced by cultured C2BBe cells would not support bacterial growth. Growth support of the media was restored by heating to 95 C for 10 min. C2BBe conditioned media had bacteriostatic activity for a large variety of gram-negative, enteropathogenic bacteria but had no effect on gram-positive bacteria.